Mom guilt

I go back to work in officially 2 weeks and my little one is staying with my mother in law, I asked for part time hours but my manager declined I have to do 3 months before I can leave but the thought of leaving her is eating me up alive, how do people deal with this? My little one has major separation anxiety and does not settle with anyone she screams at my mil or anyone and gets really worked up my partner works full time and I solo parent most the time, the thought of not being able to be with her when she’s upset or needs a cuddle or to keep her busy and knowing she is going to be hysterically crying is making me so upset .. it kills and I just can’t seem to find a part time job its killing me feel like a failure and that I don’t have the skills to find any other job other than the one am in now :(