Depressed

I’ve been depressed for almost two years, I’ve been on and off depressed since 14 ( im 18) ive only had two major falls where im really really depressed. I’ve gotten over them with god and really really focusing on good. But these two years really is hurting me. I haven’t been happy in so long I just always think about my past and my dad dying and i just wanna be happy again. Any help please !