Can an IUD give you a false reading on a pregnancy test?

Took a pregnancy test yesterday, now that im 2 weeks and a few days late for my period - And it was negative, okay great but i have ALL the symptoms as i did for my first two kids, -really tired, heartburn (i haven't changed my diet), certain smells make me sick, pain/crampiness just above my pubic bone, horrible queeziness in the am, etc.I was only with my hubby June 12-June 23 we're apart cuz of his work (yeah we had unprotected , alot.) Ive had the mirena iud in for 11 months and i have read that some women stop getting periods after a year with the iud. Im hoping thats my case but with all the other symptoms Im starting to get worried, and if the test says negative I should just believe it, I mean what im asking is - When is the best time to test? I thought it was anytime after your missed period. The 1st day of my last period was may 29. When should i retest, and if its negative i'm in the clear? I will see a dr asap but i wanna know now with at home tests.Thank you in advance