Hello, thanks for writing to HCM. Pregnancy without penetrative intercourse is highly unlikely, though not impossible. The spermatic fluid must reach the vagina for this to happen. A pregnancy test must be done after you miss your regular period, even if you experience light spotting for that cycle. If you are having menstrual irregularities, it maybe related to hormonal imbalance, which can also explain your symptoms. If the second one was like a regular period, you need not worry about a pregnancy. However if you continue to have frequent periods/spotting, I would suggest a gynecologist consult, to check on the hormonal status and also an ultrasound. Hope this helps. Take care.