Hello, and I hope I can help you today.
First of all, if you had sex three months ago without any ejaculation inside you, took the morning-after pill, and also were taking birth control pills, your chance of accidental
pregnancy are close to zero.
Secondly, your cycle will be irregular if you miss pills or change your pill taking cycle. This is not a sign of pregnancy. You need to have taken the birth control pill consecutively for three weeks straight and stop it for at least three or four days to have a withdrawal bleed from the birth control pills, so if that is not happened in the last month, there is no reason that you should expect your period to come on time.
Thirdly, the most common sign of pregnancy is missing your period by yourself, without taking any hormones. So even though there are reports of women who do not realize that they were pregnant and claim that they had their menstrual cycle throughout the pregnancy, the majority of women do not have vaginal bleeding during the pregnancy at all.
So in summary, there is no reason to suspect based on your history and symptoms that you are pregnant. If you are still concerned, modern urine pregnancy test will become positive within 10 days to two weeks after conception. So if you perform a urine pregnancy test at this time, the results will be accurate, and hopefully you can be re-sure that you are not pregnant.
I hope I was able to adequately answer your question today, and that my advice was helpful.
Best wishes,
Dr. Brown