Melatonin affecting sex drive?

Patient: I am a 18 year old male and have recently purchased melatonin from the supplement store to help me sleep better. I am not diagnosed with any sleep disorders, I just figured that it would help me get a deeper sleep. I took it 3 times in the first week (small dosages of 2mg) and noticed my libido was decreasing so I stopped the melatonin. I’ve noticed, a week later, my decrease sex drive is still persisting and it’s almost as if my penis has no sensation when I am even masturbating. I don’t know if it’s because I am lacking testosterone, or what the problems seems to be. HELP PLEASE!!!