J.F.
Definitely sounds like it's time for a check-up and a blood draw, especially if you are TTC. The sooner you get your body back in check and regular, the sooner you will probably get pregnant.
Could be hormones, diet, or another issue going on.
I have PCOS, so I've had abnormal periods since I first started, unless I was on b/c pills or taking metformin (a diabetic medication).