Ok I'm really nervous posting this but I'm desperate for some answers. Where to begin?

I would say about 4 years ago something changed within me but it's only been this past year- year and a half I've noticed it. I don't know the correct way to explain what I'm struggling with but basically I think I might be crazy- going insane, on the verge of a melt/break down.

I'm not trying to be dramatic or anything but I feel like something isn't right within me. I can't identify my emotions anymore or why certain thoughts or moods come over me. I'm highly paranoid with trust issues (although it turns out I'm right to think this way).

Best way of explaining is one moment I'll be so happy that I can't even remember what being sad is like but then literally within a moment I'm so upset- crying, thinking the worst. I can't handle it anymore.

I feel like I'm losing myself and I don't actually remember what I was like before all this conflicting thoughts came. I'm too scared to go to the doctors in case they just shrug it off and put it down to hormones or being overly dramatic.