Hi K.,
My first child went into daycare at 8 weeks too. We went to the daycare before she was born to check it out, and I cried the entire way home... mind you, this was before she born and I actually loved the facility! Leaving your baby in someone else's care is one of the hardest, saddest, and most stressful things you'll ever do.
The changes in your babies habits and moods since daycare may be due to being a bit stressed... after all, she is in a whole new environment too, with different voices, sounds, lighting and smells. It is an adjustment for her as well as for yourself. This is normal and she should be fine shortly. Daycares seem to prefer working on a schedule even if your child really doesn't have one (mine didn't), because it helps them plan/schedule their day (changings and feedings) with the other children they are caring for. If you child isn't used to one, this can sometimes cause a bit of stress at first, until they settle in.
However, it sounds to me like you are unhappy with the care she is receiving and the staff at the daycare. If that is the case, I suggest you start searching for a new facility right away (as some have waiting lists). Being satisfied with and trusting of your daycare provider is of top importance. No amount of time will change this and it will continue to stress you out. You HAVE to be comfortable with the person/people taking care of your child or the stress will consume you. Of course, you will always have little worries, but overall, you should be able to live your day normally and be happy your child is having fun, being social, and is well cared for. Perhaps a daycare with a webcam would help ease you... you could "check in" occasionally without having to go into the daycare.
Also, to me, it sounds like you have may have a bit of post-partum depression (the sadness and crying a lot). This DOES NOT mean there is something wrong with you or anything like that. Most women get it to some extent just simply due to the havoc that changing hormones cause on your body after childbirth let alone additional stressors like daycare! I definitely experieced it to a degree myself. It is important to be aware of it, because if it gets beyond your control, overtakes you, or causes a lot of interference in your relationships (like with your husband, who you need on your side for support), you should talk to a doctor about it.
My last bit of advice... if you continue to use the daycare and end up being happy with it or even if you switch, try to work around the schedule they set for your child, it will end up being easier for your baby since she is spending most of her day there, she will adjust shortly. Also, it actually helps not to constantly contact and visit the daycare. I used to do that too... the daycare was right across from where I was working so at lunch, I'd pop in to feed her, to play, to visit... her daycare was great about it, and of course, it was my right to do so... but I finally realized I was really doing it for myself (making sure she was OK, just looking at her and holding her)... in actuality, I was disrupting her day and causing more stress when I left her again for a second time as if leaving her once in the morning wasn't enough.
I had to face it, I felt guilty for leaving her and I felt that by going to see her somehow made up for it a little. I had to come to terms with the fact that she had to be in daycare because I needed to work and that was how it had to be. I came to terms with it and learned to embrace it because as time went on she thrived there, made friends, learned a lot, did fun things and liked being there. It wasn't a substitute for the care that my husband and I gave, just an alternative during the day.
Sorry this is so long, but it is a topic near to my heart. Good luck with everything!
K.
(I am currently a 34 year old stay-at-home mom of three blue-eyed beauties... a 5 year old daughter, a 3 year old son, and a one year old daughter)