what would cause the pressure on my ovaries?

Hi,
Welcome to ehealthforum,
If you are having long gaps between periods, it is possible that you have anovulatory cycles (menstrual cycles without release of egg from ovary) which usually occur during pubertal stages. Other possibilities include PCOS, ovarian suppression, hormonal derangements, etc. Hymen has passages in it that allow menstrual blood to pass out, and sperms can pass through these passages to result in pregnancy even without vaginal penetration of penis (chances are high if you were during your fertile days at the time of sexual contact). The exact cause for your symptoms can be made out only after careful evaluation. Consider visiting your doctor/gynecologist for thorough examination and further evaluation to look for the underlying cause. Treatment as appropriate (based on examination findings and investigations results) would be started to help you regulate your periods. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.