Thanks for the query.
If you had unprotected intercourse
around the time ovulation then there is possibility of pregnancy.
As urine pregnancy test kits sometimes cannot detect early pregnancy better to go for blood test
If it comes negative almost there is no possibility of pregnancy in this cycle.
Your symptoms could be because of gastroenteritis
, so better once consult physician.
In the next cycle track your ovulation with cervical mucus method or basal body temperature
method or by ovulation kit and plan intercourse around that time which will increase the possibility of pregnancy.