Suggest Treatment For Abdominal Pain After Taking BC Pill

hello, I have just one question. I'm already a few years on the pill. lately I am not menstruating when it actually needs. but when I start again I am swallowing a few days later periods do. at least I think my period. I had last week have been unwell but I was not. just a few days now I've started the pill I do. I have a strange pressure in my upper abdomen. not the normal pain associated with it. this is not unusual for me. I dare not so good for a doctor. do you advise?