Mood swings...please give advice

I have a lot of mood swings. I’m usually in either a upbeat and energetic mood, or a sad, weird mood. I’m never in between. It’s horrible because I don’t feel like I can control it. One minute I feel fine and then the next I feel horrible. One of my two moods is feeling like everything’s ok and that I’m stupid for thinking about suicide. But my other mood is like I’m sad I feel like I want to kill my self and I feel stupid for ever thinking that I could live. All my friends say that My moods don’t ever last more than 6 hours. A few people even stopped being my friends because of my mood swings. Another thing is that I’mconstantly scared of stuff. Everyday I check my windows and doors and make sure that they’re locked. I get scared that there are cameras in the flies in my room spying on me (I know weird but I do really think about that). I haven’t experienced any traumatic events. My mom says that I should just eat better and my moods will even out which makes no sense to me. I just want to feel ok.