Big hugs my love this TTC gig is a tough one sometimes.

It is just not factual that you can get pregnant at anytime of the month. We women are designed so that we are fertile for a short period each month. Sperm live longer than ovum so, this adds some time on. It is thought that sperm can live for up to 5 days in the "right environment". If I were you I would hop on line and grab some OPK's. This will help to pin point your LH surge. This surge occurs just prior to ovulation. Do this for a couple of months (opk's can be a bit tricky but that's a whole other post!) and just see when it is you ovulate. When you dtd at this optimal fertile time pregnancy is likely to happen sooner than just 'winging" it. Have you got a copy of the "Billings Method". This is a great book to help you see the signs your body puts out throughout your cycle. This will help you also to pin point your fertile time more confidently.
Wishing you a speedy