Trying to conceive after pill

I've been off the pill now since jan 09 and before that i had regular periods of 28 days. In feb my period was 31 days and in march 33 days. I decided last month to start using an ovulation kit and got a strong surge on 4/11 (evening) and an extremely strong surge on 4/12 (early afternoon). My husband and I have been having sex regularly but did it 4/8,4/11,4/12 and 4/15. I'm trying to figure out the likelyhood of me getting pregnant. Any advice would be great.Thx;0