+OPK.....YESTERDAY...what do i do now?

Lmp was 3/26-3/30...fiance and I been babydancing since Apr. 1st.....babydanced this morning and it was almost dreadful having it was painful in lower abdomen....now I'm having twinging cramping on and off in lower stomach....I don't know what possibly could be going on because AF is not due until 4/23.....I have had 3 miscarriages and a blighted ovum(which is a false pregnancy where the embryo pretty much aborts itself)....I'm so terrified of what might become because these little cramps are becoming more and more horrid......so how long should I wait to test??...I have a Dr. Appt on 4/17..would a blood test show BFP by next Fri....help......I need all the advice I can get....thanks so much and TRUCK LOADS OF BABY DUST TO THOSE TTC.........p.s.....the miscarriages and false pregnancy was about 7 yrs ago......