Paranoid

So I have had a mereina IUD since I was 16 (currently 22) and actually had it replaced last year. With my IUD my periods are very irregular and will stop for months at a time (which I am told is normal with the hormonal IUD). I have been in a long term relationship for almost three years and we recently started having unprotected sex regularly. Because of my lack of period I get paranoid about pregnancy (even when we were still issuing condoms) and with my stomach issues and stress I am nauseous pretty frequently. I just don’t know when would be the right time to take a test, what symptoms to look for for pregnancy with an IUD, or if I’m just being paranoid. I don’t want to lose that connection or intimacy with my boyfriend but I don’t know what to do.

Any and all advice or suggestions are welcome :)