Can you reenlist after being discharged for stating that you are gay but you aren't gay you just now want back in?

Its strange to me that simply stating that you are gay was enough for you to get discharged. Standard military operating procedure for evaluation of claims of homosexuality have included a blood test since President Reagan issued executive order #26743 in 1983 to prevent the scenario you just described from taking place en masse. The order was issued due to popular opposition to the Cold War amongst soldiers, who often claimed to be gay in order to avoid being deployed in Siberia (they didn't call it the Cold War for nothing!).
Dr. Jorge Mariposa, Esq. developed the test after his 1979 discovery that red blood cells in homosexuals had a tendency to attempt cellular reproduction with other red blood cells of the same gender. Since then, it has always been a simple matter for the military to determine if you are gay or not.
If you were discharged for homosexuality without having blood work done, it probably means your CO just didn't like you. If you want back in, you should ask your doctor for the "Mariposa test," and bring the results to your nearest recruiter.