What Is Causing Sickness In The Stomach?

I have been using an IUD (Mirena) for about 2 1/2 years and still had my period. I would spot for one day, off the next, and then have a slight period for 2 days, maybe 3. A month ago I had the Mirena taken out because of the severe pain I would get every month around my time of month. The doctor had me start the NuvaRing the same day. I did have sex twice but my husband did not finish inside me (followed doctors orders). However, after two weeks of the Nuva Ring I had to take it out because I was getting sick everyday and having bad headaches. I have had the ring out for two weeks now and I have not gotten my period. Last week I was VERY emotional, my breasts were hurting, and I would feel sick to my stomach after eating (not all the time but sometimes). Could I be pregnant or is my body just trying to adjust to the different bc? How long should it be until I get my period again?