Unusual cycle messing up my fertile week

So my cycle is usually a 28 day cycle but last month it came on day 31 which it never does so I’m almost 90% positive I had a miscarriage so now glow is basing my cycle off of an 31 day cycle. Should I go off of the 28 day or 31 cycle. We are trying for a baby again and for the 31 day cycle it said my fertile week is April 10-16 and for 28 it says the April 6-12 me and my SO baby danced 8,9,13,14,15 . I’m hoping this time we conceived but I’m not sure when I was fertile. Anyone still think we have a strong chance either way ?