TTC, intermittant pain LHS, late period, then clotting

Very unusual symptoms this month. Can anyone help please? Have been TTC for years including 3x IVF cycles. Decided to try naturally again. Periods usually regularly irregular ie 25-31 days. However this month I had an intermittant tug and pain in left hand side at front of body, but not low enough to be ovaries. This went on for a couple of weeks. Period was 4-5 days late. The pain had subsided then, without warning period came. Period is a lot different than usual with symptoms I have never experienced before so im a bit concerned. I have a heavy bleed with lots of small blood clots. The pain in lhs is receding, but I have the usual cramping in lower abdomen, ovary area. I will be making a Dr appt. on Monday as this is all very unusual for me. Can anyone help? Has anyone had similar symptoms and if so do they know what was the cause? Thankyou.