better to have intercourse around the time of ovulation, as the sperm can be viable in female genital tract for around 5 days in case of ideal conditions, there is possibility for fertilization,
anyhow your symptoms may also be because of the drugs you are using,
so you wait till the expected date of periods and undergo blood test
which will find out the possibility,
meanwhile continue to take folic acid
and vitamin tablets, you can take antacids with your doctor's advice for relief of symptoms.