Positive pregnancy tests on nexplanon!?

Hello everyone, I’ve had nexplanon for almost two years now but lately been feeling very off/strange decided to take a pregnancy test expecting it to be negative but I got a faint positive to my surprise. Took another later on also looked to be positive. So went out bought more tests. Took a total of 8 tests..6 came out with positives (some were fainter than others but still there!) and 2 negatives. Set up a doc appointment the tested my urine told me it came back negative.. I have symptoms like mild cramping and peeing often. Also my nexplanon is starting to HURT in my arm. I have no idea what’s going on.. any advice/ideas?! Could I actually be pregnant but just early so it came back negative at doctors office?? Help