Alright, I'll tell ya this hon, if you think it's in your head- yes get a pregnancy test. If it comes out negative, and you're still worried, wait until your next period. If you don't have it by a week after the due date, take another HPT test.
I read on some medical site that the two true signs of pregnancy is a missed period and a positive HPT test. Even though the other symptoms you experience may be common for pregnancies, it may be other problems with the pill you were taking. I would still recommend getting an HPT test, if you're not ready to tell your boyfriend before the test, then don't. Go on your own, or take a close girlfriend. Having others with you makes it seem easier, instead of like everyone's watching you.
DON'T stress. I just went through all kinds of anxiety worrying if I was pregnant. I'm not. Stress can cause your period to miss or be late by a lot of time! Just relax and enjoy your time. Best of luck hon! Keep us posted!