Can't do this alone anymore

I feel like such a failure idk what to do anymore 😔. I just turned 19 and I have a 7 month old baby boy, my bf passed away in November, I'm living with his mom and stepdad right now.and it's been alright, they help me out a lot but recently his mom has been really depressed and I try not to bother her with anything. Right now I'm just exhausted. He still wakes multiple times a night, I work 34 hours a week. My schedule is tough tho. I work nights from 5 to just past midnight, I usually get around 4-5 hours asleep a night, I do dancing and I've been doing dance since I was a toddler, my goal is to someday become a dance teacher but it's so exhausting I'll go to my class 3 hours three days a week and on the day's I don't have class I still try to get a jog in, plus I'm taking online classes for college as well. Plus on top of all this I still have an infant to take care of. I don't want to quit dance because it's the only thing that keeps me happy and keeps me going I love expressing myself and my feelings through dance it such an amazing outlet for me, I'm doing fine supporting my baby j don't pay rent but I pay for all my son's stuff and I do help with groceries, Im just so exhausted and feeling really down and lonely. I try and see my dad weekly but I haven't felt like seeing anyone or doing anything, some mornings I just sit in the shower and cry. I miss my bf so much and I just don't feel like I'm enjoying my son's infant years because I'm to exhausted so I feel like a shitty mom. Everything in my bfs.hpuse is tense because they are grieving as well, my dad said I could move back in with him but being in his house is to hard my brother passed away back in May In that house and I just can't be there. And see his room and everything it's to hard, he's trying to sell it but no hits yet. I don't even know if this is making sense at all or what I'm trying to find by posting this. I guess I just feel empty and I feel.all alone I don't have time to see a therapist nor can I afford one. I just don't know anymore. Also my mom's not really in my life anymore and I really miss her a lot these days.