Understanding My Depression: The Constant Switching of Emotions

i don’t understand how my depression works. like one second i’ll be suicidal, then the next my brain decides that it’s tired of being sad and decides to be fine. like for example, literally 5 minutes ago i was sobbing my eyes out bc of how much i hate myself, then after like an hour of crying, i just stopped. it’s not like i don’t believe what i was just crying about, but my brain just decided to stop caring. like i’m so calm now and that scares me bc usually it can turn into a manic sort of happiness that leads me to believe i’m completely satisfied with everything in my life when in reality i’m not. it’s like idk who i am bc i feel so many different things and it keeps switching all the time. like i’ll fantasize about breaking up with my partner bc i’ll feel so unhappy about our relationship, but then i’ll have a good moment with him and remember how much i love him. there’s not rly problems in our relationship, it’s just my brain deciding to be sad and sensitive about everything. idk how to put it in words, but i feel like i feel multiple emotions at once and my brain/body can’t decide which to feel at a given time. like i can love myself and hate myself at the same time and both are true to what i believe. i really don’t know how to explain it or if anyone really gets what i’m saying.