My period has always been irregular the longest I went w/o my period is 2 months and that happen only once. My regular period pattern is I would come on for 2 months then skip a month and so on. Me and my boyfriend had sex and he did nut in me and every time we had sex after that day he still did. My period stop and is still not on. I went to the doctor and gave a blood test. The test came back I was not pregnant but my period still isn't on and this makes 4 months now 5 months will be next week. Why is has my period completely stopped if I'm not pregnant?

What sort of medication are you on? Do you have any known medical issues? IE PCOS, Diabetes, Thyroid, etc. Do you have weight issues, IE Severely under or over weight? Are you experiencing any illness? How old are you?

There are three thoughts here, one it is too early to test positive. The second is more complex. Your periods are irregular and you haven't missed more then one beforehand. You could be missing more then one now. Just the way your hormones are working at the moment. Varients of this happen to most women at some point. You'll have a set pattern and rhythm to your periods until you have a wonky period or two. There could be absolutely no reason for it. The last thought is that it is a secondary medical issue whose side effect is irregular periods.

This is something you'll need to spend more time with your doctor with. They're more suited to understand what is going on here.

If there is an underlying medical issue that has caused your periods to be irregular then it may have gotten worst. There may be some hormonal change in your body due to several reasons. Stress worry, changes in life style are all possible reasons.

A medical exam by your doctor is the only way you will determine the cause