Mouse clicks not registering

ok so basically ive been playing for a good 5 years now and never had this problem till now, what happens is when i click in front of me and behind me quickly the behind me click doesn't go through, its not my ping im always at 30 ping, when i click side to side sometime the same issues happen. my fps is always at <200. i dont know what is causing this. i scanned for malware and deleted everything that was suspected and it still happens. it makes the game unplayable. I just played a game on kennen and as i was e'ing through the wave it continued to go straight since it wouldnt go back when i clicked and i ended up dying to being hooked to a blitz into a tower. Please someone help i just wanna play again.