Stay at home mom, seriously any tips?

So I'm 21, I have a 3 year old daughter and a stepson that we have 3/2. He is 18 months. We just moved but I been a home stay mom for over a year. I'm loosing it.. I need advice, tips, or anything!. I love my kiddos, when my stepson is here things are so rough since he hits a lot, he is rough boy. It keeps me 100% busy on them 2. But when he is gone and it's only me and my daughter, she is calm, sweet, organized, she listens, it's like taking a long break lol I teach her so be so independent it's amazing :0 of course I cook, clean, teach her things, all those things. But I feel like I have Too much of "me time" and I got absolutely nothing. I want to get a job, but childcare.. Is too expensive and we only have one car, and it's very difficult. My husband he isn't really a part of "us" kids and me. He works and comes home and his games, TV, which I honestly just don't mind.. But I feel so alone.. So sad, depressed (I'm taking meds now). I got no friends. I just don't know how to keep going. We been even trying for another baby, I know I want another baby so he/she isn't so separated from them. But also I feel like.. Its going to keepe busy 24/7 and I like that?. Any good hobbies? Any ideas? Any advice?. I want to maybe get a job to be around people ND feel like I have accomplish something.. But I would miss my kids so much and I be working t to pay daycare. :/