Can anyone tell pls why i am having obsessive sexual thoughts

Because your body is use to doing it often and you trying to abstain goes against your bodies regular routine. Try to find something to do that involves not using the internet.

 

Go out and do something, and stay away from the source of your sexual OCD (PMO or not).
A thought of a woman, like a small candle fire, can easily turn into a P movie in your head, like flames on your drapes. Keep it up long enough, the whole building is in ashes and you’ve lost a the fight. Anything can lead you to think about the filthy stuff such as “mmm.. Cheetos on the beach.. oooh girls on the beach.. aaahh girls.” And that’s were you take your two fingers and put the candle out. Plenty of these will occur through out the day, you must be aware of that evil spark before it grows and devours the house, your brain.

 

Abstain from the internet for one day man.