R.J.
I've had paraguard for a little over 8 years now. About twice a year I get super crampy periods and they run late (like 36 days instead of 28). I did this as a teenager as well, though. Tends to happen right around autumn equinox and spring equinox.
2 other things which will IMMEDIATELY throw my period for a loop (since there are no hormones forcing it to come no matter what) are dieting and stress. Either can keep me period free for several months at a time or just massively throw off my cycle. Since there are no hormones forcing things along, my period is a lot more sensitive to how well I'm taking care of myself.
The vast majority of the exceedingly rare pregnancy-while-on-paraguard happen that first month... aka a woman was already solidly implanted with a fertilized egg when the IUD gets implanted... and several years later if the IUD embeds partially or wholly. Even then, you have a better chance of being preggers after getting a tubal ligation than getting preggers on paraguard. So personally... I'd check my diet, sleep, stress levels... and if those are all normal & healthy... wait a week and go in and check placement. Pregnancy is possible, just extraordinarily unlikely since yours is new (but you've already had several periods).