I'm confused

Hey everyone, so I've been with my boyfriend for 2 years (I'm 16) but I can't help myself having negative thoughts all the time like what would it be like to be single and recently I met this other guy and I couldn't help but want to flirt coz we got on so well but then because I had a boyfriend which is fair enough he went for someone else in the end but I couldn't help but feel jealous. Ahhh does anyone else have this and is it a sign I shouldn't be in a relationship with him because also, we argue so much and I really cant stand him sometimes.