how do I deal with depression

I'm 20 years old and moved out with my boyfriend, he currently works a full time job and I've been in between jobs multiple times because of multiple reasons. I'm constantly home and can't get myself to go out of the apartment, I find it hard to get out of bed, I'm constantly tired and my sleep schedule is super inconsistent. I am sad so often and often have thoughts about suicide though I know I won't take action. I'm so very in love with my boyfriend (soon to be fiancé) and I'm very happy with him and our cat but it feels like I'm stuck in this endless loop and trying to crawl up out of this deep dark hole. I cry often and wish I would just feel better afterwards but I don't. I can't afford to see a doctor to talk to them about this and i can't tell my parents that I'm that broke. I'm starting a full time job soon but I'm so worried I'm going to mess that up too because of this sadness and tiredness and emptiness i feel. I've lost the will to do so much and i just don't know what to do anymore. I know I have so much to be happy for, I just can't make myself be happy. I don't want to self diagnose myself with depression but, I feel like this is what it is and I don't know what to do...