Very Clingy 2Yr Old

I think you are finding out that it's impossible to work while you are looking after a child.
You have to get a sitter or put her in day care.
Working at home is the same as working from the office without the commute.
It's not abandonment issues.
It's separation anxiety - and it's very common and every baby/toddler/preschooler goes through it to some degree - some are way more intense about it than others.
My son spent most of his first 3.5 years on my lap when ever we were together.
Even through the first few birthday parties he was invited to.
Dad would do if I wasn't available but the minute I walked into the same room our son would almost lunge out of Dads arms to get to me.
I was 'the Mama' - everyone else was 'not the Mama'.
He did outgrow it eventually.
You probably have a year or more to get through yet before she becomes a bit more outgoing.
Get her into daycare where she can play with other kids and get attention while you work.

Unless she has been told "your birth mother abandoned you," there is no way that a 2 year old who has been raised by you since her 5th day of life could feel any abandonment.

It is pretty normal for a child of that age to be attached. My youngest is almost 2 and he hates it when I do something that doesn't involve him. When I am typing, he comes up and takes my hands off the keyboard. When I am sitting on the sofa with my 3 yr old on my lap, he comes up and tries to pull him off yelling, "My mama!" That's just the way they are right now.

Smother her with love. Give her doses of attention, and then work for a while...then come back and give her more attention...and then work again. Working from home is VERY difficult when you have small children at home, unless you could get someone like a mother's helper to come in and play with your daughter while you do some work.

I don't think it is bc of her bio mom, unless u told her. Please accept her temperament and dont go crazy making yourself and her feel badly. It will be hard but she needs to be in day care. My DD is over 3 and just getting over clingyness to.me. it takes time...

I don't think it's an abandonment issue with her mom. 5 days old? Honey, she thinks you are her mom. It's only you who is in denial. A 2 yr old NEEDS attention. It's not psychological maladjustment. It's a developmentally appropriate response to her mom, you, being unavailable.
If you need to work, you need someone to watch her.

Instead of resenting her, try understanding her needs and developmental milestones. Read some parenting books, like LOve and Logic. Whether you like it or not, You are the significant parent in her life. It probably wasn't what you had planned. Where is your H in all this? It's his responsibility to see to her needs. Family counseling sounds like a good idea to get everybody on the same page and pour some wisdom into your lives. Otherwise, I fear for this little girl.

Is there a developmental pediatrician in your area...To assist you?

See if there is a two's program that she can attend just a couple of mornings.

She doesn't have abandonment issues. Not from 5 days old.

You've spoiled her and failed to set limits. Tell her "No, Mommy has to do this now," and give her something to do nearby. It's OKAY for her to get mad and upset. All she has to learn is that you WILL come back and play with her when you're done.

It's developmentally normal for EVERY 2 year old to want to monopolize all of your attention and always be in your arms. It has nothing to do with her birth mother. It's up to you as her parents to teach her to be independent and be able to feel secure playing on her own, sleeping on her own, or going potty on her own. It takes time and practice.

It's most likely normal separaton anxiety. My child had that.
They just want to make sure their primary caretaker (you) that they love
doesn't go anywhere.
You are her love & protector.
Most likely it's just the passing phase of separation anxiety & she'll get
through this stage very soon.
Just hug her & pay attention to her for 15 mins tretches THEN put her
down to get your work done. Then be sure to back to her & do the same
thing again.
The cup & potty thing are not likely tied to you at all! Just a normal stage
of "they develop on their own & not by hard fast text book rules". She
will come to get those things (potty, drinking from a reg cup, pooping in
the toilet ect) in due time.
Just reassure her, shower her w/love then get your stuff done then come
back to her to give her attention. Cycle like that. Not as ideal for you to
get your work done but this stage will soon pass.

I'm going to agree with most of what's below. That said, she could be experiencing what Nancy Verrier terms "the primal wound". (Here's a link to the book on Amazon ... http://www.amazon.com/Primal-Wound-Understanding-Adopted-....

Ok, that said ... as a foster / adoptive mother of a 5 week old who is now 2, I personally disagree with portions of her theory. however, during our foster parent book group, another foster mom who's also an adoptee felt like much of the book was on target. So, perhaps read through it and see what you think. If nothing else, it's arming you with knowledge about what some adoptees may feel.

For what it's worth, my 2 yo is also very clingy to some of the same extent as your little girl, but we have some pretty serious separation anxiety because of visitation until he was 18 months old. We tend to follow the Circle of Security model and give him what he needs to help him move through this stage.