How Long Will Be The Ovulation Period In Healthy Women?

I ve recently stopped my birth control about 3 weeks ago I m trying to get pregnant and I ve been taking the true blue ovulation test for the past 4 days and its saying that I m at my peak but from what I understand you re only supposed to ovulate for 24 to 48 hours is there a good possibility that I am pregnant me and my husband have been having sex everyday and why does it say I m ovulating at my peak for 4 days straight is it because I just recently stopped my birth conovulation. What is the chance I m pregnant