PCOD and periods. Pregnant till labour?

In September I had lower abdomen ultrasound for my painful periods.They used to come every month but very painful and cycles kept fluctuating from from 25-32 days.The reports were normal and my gynaecologist prescribed me norethisterone tablets which I took for a month but it gave me digestive and gastric issues.In October I discontinued the pills but had to take it for 3 days as my periods didn't arrive. From Nov. to Jan.I was on ovral-G.On 11th Feb.the 6th day of my last withdrawal bleeding from ovral-G I got another ultrasound which diagnosed me with PCOD.In between I had many intimacies with my partner but never had penetrative intercourse only fingering dry humping and dry grinding but I am not known about the sperm presence.My latest ultrasound showed empty uterine cavity. How can I get my natural periods on time now because I am off ovral-G also having PCOD?Also can I be pregnant I got to know something as cryptic pregnancy when you don't know you are pregnant till labour?