Possible Sign of Pregnancy?

I know you get alot of people asking this question but here are my reasons for concern. I am currently on the pill. Have been for 3 years...Became pregnant once shortly after starting the pill but had a miscarriage with in the first month. I was supposed to have gotten my period this past wensday. My period is always regular lasting wensday through sunday. But instead I got it the next evening(thursday). It lasted only that night and was very very short and light minor to no cramps ( lightly spotted my tampon). It was gone this morning. I checked my pill pack and realized I missed 4 pills this month not in all in a row. And none of my first week pills. This rarely ever happens. If I miss 3 pills in a row I usualy start spotting the 4th day. I never take my sugar pills and one of the pills I missed was this past saturday (day before 1st sugar pill). Which means I should have at least started spotting by tuesday. I know this becuase i've missed this pill before. I had intercourse with my husband through out the month and I am not sure if any occured on the missed days. I am usualy very good about this and skip intercourse on any missed days. Other minor signs are I did not experience my monthly mood swing which surprised my husband lol. Instead I was cuddly also I didnt not experience blemishes like I always do. Should I consider a hpt or do you think this is just one of the side affects of the pill? I know that an occasional missed period is a sympton of prolonged use of the pill...A gyno told me one time. Do I have reason for concern?

I appreciate your help and feedback on this. If you need me to explain more or elaborate just ask. :d thanks all