period help

so my period is 2 weeks late, I have done 4 tests and all have come back negative, it's beginning to really stress me out now because I can't understand why I have no period
I came off the pill in November because it was completely messing with my body, and I haven't gone on anything else yet, I've had two regular periods since I've come off it.
could coming off the pill have messed up my cycle???