Late Period, Negative Pregnancy Test

I had my IUD removed in late December and never had my period with my IUD. Luckily I got my period 3 days after removal so we could start tracking easier while TTC. I have no idea my cycle length but I’m now at 36 days and no period. I took a couple pregnancy tests over the last week that both came back negative. I assume this is normal after IUD removal, but it’s much more challenging now to track. Do I still start my new tracking month on day 1 of my period and assume day 14 is ovulation day like last time? Of course I’ll still use Ovulation Test Strips, but I’m just confused and wondering if anyone’s experienced anything similar and if I’m basically starting from scratch now or if I can go off of any of my data from last time.