Struggling

I’m worried about myself. Lately I’ve been feeling depressed and hopeless about life. My boyfriend tries as best as he can to be there for me but I still feel the same. I’ve also been questioning our relationship and if I even wanna marry him or am I just wasting time. I feel horrible because he’s a good guy but sometimes I just go through these spells where I don’t even see us getting married in the future then I’ll change my mind and feel like I do. Idk he doesn’t deserve someone like that ( literally crying while I type) I’m confused and I’m just tired of being confused I just wanna be certain about something in my life