I didn't get my period

Yesterday was the second time in the last 2 months that I missed my period. Now it might be coming late this month cause my pattern is usually a bit messed up but what if it doesn't. If it doesn't it would be the second month I didn't get my period. But I can't be pregnant I'm a virgin and as for oral sex the last time that happened I got my period 2 week later so it can't be that right ?