Given that we've now established (on your other thread) that you're approaching the age of 14, I can assure you that the way you're feeling is perfectly NORMAL (or, at least, 'well within the range of normality'). That's based upon:
(a) "Been there, done that" (Yes, even though I'm 63 I really can still remember what it was like being a teenager!) ; and
(b) having taught many, many teenagers who were obviously experiencing very similar feelings.
So you're most definitely not alone!
Finding someone to talk to about the way you're feeling might help. Yes, I know that can be a lot harder than it sounds but there will be someone who can help you, whether that be a parent, a favourite teacher, your form tutor, your head of year, a youth club leader or even your doctor. I mention your doctor because, when I was a teenager, that's who I ended up talking to. He suggested taking vitamin B supplements and they seemed to work but, looking back at the experience now, I suspect that it was simply talking to someone which really 'did the trick' for me.