Whats wrong with me? Why don't I want my baby anymore?

I am 21 and my daughter is 18months old. I had her because I didnt want an abortion. She was a 26week prem baby and never had a midwife or doctor looking after me or her she just had NICU. She began sleeping through the night at 10 months but for the past 3 weeks she has been waking ever 2 hours and doesnt want to go to sleep. When I bring her home from daycare she is grumpy and moans all the time and just wants to be carried around.. She cries all the time until she gets what she wants. I basically have 2-4 hours of sleep every night since she began doing this. I look foward to going to work so I can have a break from her. I love her but im at my wits end. i dont know what to do anymore.