Why don't girls like me?

So I'm 17 year old guy and no I'm not a massive nerd or a weirdo or anything like that, I've had girlfriends and got with girls at parties before but this year it seems no girl has taken an interest in me whatsoever. I have a few girls who are really good friends, one of my best friends is a girl so I don't have issues speaking to girls or anything it's just none seem to see me as a potential boyfriend. I'm not the fittest guy. I don't have the best skin as I used to have acne. My hair is alright looking. Physically I'm not that good. I'm not fat but im not toned so I have a little belly and small love handles which I am desperately trying to lose over the next few weeks and months with diet and exercise. I've been told I'm really witty, kind and caring so I know I'm not some socially awkward guy I'm also aware of not being the nice guy or the friend to girls so I always try and keep my distance and don't hang around a certain girl 24/7 or text/phone them all the time and breath down their necks. Is there some fundamental thing I'm doing wrong or should be doing? Am I actually not coming across strong enough? Should I be texting girls more? Any advice??