got tested for std dr said test came back negative

Got tested for std came back negative but i get stomach pain every ones in a while & when i push on my stomach it hurts around my belly button area also got tested for a yeast dr said i did have a yeast infection said i had alot of discharge and she was going to give me antibiotics then when i called and asked if my prescription was ready dr was saying i didnt have any infections but recently my vagina is itcy and a bit tender could the test be wrong about the std its been over 2 weeks since i got tested and i called back just to make sure and still said i didnt have an std should i go get tested again incase the test was wrong ? I had an std when i was young by my ex who cheated he got tested told me he had it and i got treated i also had symptoms then to the point where i would feel so dizzy and severe stomach pain. But it doesnt feel the same as when i was younger.