I am in a round of doxycycline. will this interfere with an std test results. should i wait a certain amount of time before testing after the doxycycline?

yes to both

It depends on the particular STD, your doxycycline dose, and how long you have been taking it. If the usual STD dosage (100 mg twice daily for 7 days), negative gonorrhea, chlamydia, and syphilis after completing treatment are not false negative but true negative results. They cannot tell whether you were infected and cured, or if you were never infected.