I get afraid and nervous when someone likes me.

I’m 17, and at the start of the year, this one boy had a serious crush on me. To the point where all his friends knew, and I knew and apparently he still likes me.
When I found out I felt so anxious and I don’t know why. Is it because my parents are strict when it comes to boys and going out? Idk

Another boy likes me now, I can just tell by the way he talks to me and looks at me from across the room. He’s really sweet but over the weekend, I’ve just been getting this nervous anxious feeling in my stomach. I don’t have an attraction to him back, but I like talking to him and I sit next to him in maths.

The first time this ever happened, when I was in yr11, things did not end so well. This guy I had been really good friends with for years, well we both got closer and we both developed strong feelings for each other. To the point where I still have feelings for him now, and I really feel like he partially still likes me now too even though he’s been in a year relationship with his girlfriend. We both loved each other so much, but I just couldn’t admit it to him. I would always get that nervous feeling in my stomach and I’d always feel anxious about it and I hated the feeling. As a result of that, I started to act horrible towards him so that he’d hate me and the feelings would go away.
I haven’t spoken to him in a whole year, but almost on a daily basis he looks at me but I try to ignore him. The worst thing would be to destroy his relationship with his girlfriend.