I have a cough and my body feel weak and i cant taste anything really. but im fully vaccinated i havent had my booster shot yet?

You are still at risk for Covid-19 infection, unfortunately. If you do want to have antigen test done, you should isolate your self as much as possible. At this season, we cannot tell if you have flu or covid-19 infection. I suggest you should have tests done for both conditions then go from there. Whatever the cause, you are relatively young and vaccinated x 2, so you should be fine.