Lmp 3-20 took clomid (clomiphene) days 5-9 already have positive ovulation test is it possible to ovulate so soon?

Yes: Today would be d 11 of your cycle and the ovulation test can turn positive 24-36 hours before you actually ovulate. It is possible that you will ovulate on d13 which would not be unheard of on that regimen.

Possible: I have no idea what today is as you did not put a date. Most women will ovulate between day 10-20 on clomid, (clomiphene) more commonly from day 14-18.