First time poster TTC

Hello! My husband and I are in our first week of TTC. I came off the pill (cerazette) a week ago and off antidepressants (slowly) for anxiety and was so excited to start trying. For the past 3 days I’ve had mild abdominal cramps, like period pain, but with no blood, right in the middle. I expected to have a withdrawal bleed or period soon (the pill stopped my periods, it’s been years since I had one), but the pains are getting annoying- what’s going on? Also really tired with a headache. And to think I had my hopes up that it was really early implantation pains... or is it just medication withdrawal? ovulation test is negative