Not adjusting with two... help!

I just had my second baby girl on December 28th and since I’ve had her I am either bf her or I’m trying to get her to sleep, the problem is that I also have a 4 year old who has nursery mon-fri 8.50 to 11.50 and my mum has been taking her there and lifting her again, I feel like a failure since every time I try to do this I can’t get out of the house on time and have to call my mum, this also happens anytime I try to leave the house so I haven’t gone anywhere with both girls by myself. I suffer from an Anxiety disorder but haven’t been on medication since I got pregnant and now I don’t know if it’s that or postpartum depression that’s making me feel so down all the time. I feel guilty constantly and can’t enjoy this time with my girls. Has anyone else found it difficult finding time with 2 kids?