Please help!!

I had a sonogram on 12/29 and had two very large follicles. I triggered in the office even though the doctor said I was prob starting to surge in my own. I had a little cramping mon night and figured I was ovulating and went for my IUI the following day. My ? Is on 1/1 I had super intense cramping prob some of the worst I've ever had. Any idea why? I don't think I ovulated more then 3 days after my trigger. I've always ovulated within 30 hrs of taking it in the past