Why is your daughter still on the bottle and not potty trained? Have you taken her to a pediatrician for checkups? If so, what does he suggest? If not, make an appointment now. A pediatrician is good support. He an make recommendations and even refer you to get more support.
A friends 3yo daughter needed to be trained before she could go to daycare. SHE was diaper free in one week. Her mother took her in the bathroom with her everytime she (the mother) used the bathroom. Her daughter sat on the little potty. Mom talked about what a big girl she was. This little girl wanted to be a big girl.
I suggest that your daughter wants to bE a baby like her little sibling so his may not work. It sounds like you've treated her like a aby and now that you have set baby you want her to grow up. YOU can turn this around by being patient and knowing it will take months. Read about child development and parenting to help you. ASK a librarian to help you.
If this 3 yo has come to live with you from a prior home, she's likely to be very insecure. SHE needs a routine and sense of security. You can begin to provide this by having a routine for eating, sleeping and playing.
I suggest you sit down with her while she eats. Have a specific bedtime with a routine. PERHAPS bath, a bit of snuggling while you read her a story, hugs and a "good night."
My daughter as 5 kids, including a 5 month old, three and a 5 yo. When the baby is the age of yours she sometimes included the baby in storytime.
My daughter is low income and is the the mother she is now because she did get help from state and county agencies. SHE and her husband are still low income. I can't remember the programs name. THE program provides formula and we'll baby check ups. They also have insurance coverage through the Oregon HealHealth Plan. The plan is separate from Obamacare.
I suggest that you include the 3 yo as much as possible with the care of the baby. SHE can hand you a diaper, a wipe. My 3 yo granddaughter loves putting the diaper in he trash. Mom talks about the differences between babies and big girls. Somehow, she makes it sound like being a big girl and helping mommy to be the best thing.
I suggest you will be be to breathe when you find aaway to influence the times she's physically close. I guest that the more time you spend with hER , she will eventually be less needy. THIS will take time. She feels very insecure aND pushed to the side. EVentually, with you being consistent in giving her love , attention, and routine she will be less needy. This will take weeks or months depending on how she' been treated up til now.
If you re low income, you can eligible for county and state support. YOU can have the support of a pediatrician and a social worker.
I also suggest making an an appointment through the school district for alsoppointment evaluation. Federal law requires school districts to provide services to families and children from birth on who need extra support to ensure success in school.
Sounds like this little girl is not your child by birth. Where are hER parents? Why do you have hER without support? Even if she's your birth child, the county and state may be able to help you.