Please fapstronauts, tell me is something wrong with me ?

Hi, I really need help with this... first of all, I am almost 16 years old male and I used to watch porn often, but in the last 4 or 5 months I almost gave up on it... I have masturbated maybe no more than 6 times since then.. I have noticed some weird changes into me... first of all I had very low sex drive, wasn't interested in sex all... then I though I had PIED, but eventually I found out I can get it up by thinking...However, the thing is its not as hard as if I am watching bit titty pornstarsor sth like that, then my penis might explode.. for example If I browse bikini models of Instagram I get an erection but its not that hard... the first 2 or 3 times in a day I get a hard erection by it but after that it seems to be exhausted or sth like that.. I do get morning wood but again it is kind of weird, it was harder before... can someone tell me is this any problem or sth ??