Calculating Due Date Cycle After Chemical Pregnancy?

So, I had a chemical pregnancy in the beginning of May, about a week after my period was supposed to come. My period started May 3 and only lasted about 3 days of super light spotting, then on May 8, I started feeling cranky and went to the bathroom to find multiple clots and heavy dark blood. I continued to heavily bleed for about 4-5 days. Well, about a week and a half- two weeks after that, I was ovulating, so we just decided to try anyways... well it worked. I've never been pregnant previously. So my question is, how do you calculate your due date? Is it still off of my LMP (May 3) or the day my bleeding with the MC started (May 8)? I know it's not a huge deal and I'm going to the Dr's on Wednesday morning, I'm just curious and my mind is racing/wandering! Thanks in advance!