Just a rant

So my boyfriend of 6 years moved out about a month ago leaving me to take care of our 2 kids 24/7 by myself. I was already doing everything for the kids but now I don’t even have him here to watch them while I get a bath. He’s been staying here pretty much everyday for the past week but left today because we got in an argument and he was pissed that I wouldn’t let him smoke weed. I’ve been using my grandmothers car since mine messed up a few years ago which I’m very thankful for and try to take care of it. Well I’m starting to get really upset because I wanna get a job but my grandmother said I can’t use her car to go to work. I don’t wanna use my moms due to she has a full time job and would also be watching my kids if i worked so she needs it to be able to do errands while I’m at work. I feel so useless and a terrible mother that I can’t provide for my kids by myself