Any single moms here? Or anyone with advice. How do you balance work, children, social life, relationships?

Short backstory, i am 23 years old, my son is almost 3 years old. Me and his dad split when he was just a few months old due to his lies and cheating multiple times. He has a gf now and we coparent 50/50 for the most part. I got into another relationship, But we just recently broke up over a month ago and he was my boyfriend of 2 years whom i moved in with with. Now i feel awakened. I was scraping by with making over $30 hour at my part time job but now, post breakup and less support its not enough. I will be starting a new full time job soon on top of my part time job, and i will be alighting my schedules so that i have 2 same set days off to dedicate to my son, and myself. Well, im so nervous to start my new job, though its not a tough one, im worried i will be tired all the time, and miserable or get depressed. I see some of my current single coworkers work almost 70 hour weeks with multiple kids to support them, and they seem drained and depressed. I want and need this money more than anything. To support my son, to get a new reliable car, get a new place or apartment. And no theres no way for my to work overtime at my new job, i do eventually want to finish the road to my degree once my son is in school, if possible. After breaking up with my boyfriend, it was hard but i feel much more determined to go after what i want and stay single, and focus on my credit. finances, and saving more. I just am worried i wont have the strength in the midst of it all… im young, none of my old friends relate they are out at bars and getting their masters and enjoying life. But since getting pregnant at 19, Its lonely. any tips from single moms out there? Or from anyone that can offer advice?