While it wasn't smart, the main thing is not to repeat past mistakes.

Obviously there is a higher risk of STD infection with someone who may have many sex partners.  However most top professional providers are pretty good about using precautions and being tested.  They didn't get where they were, and in some cases spend many years providing without being VERY careful.

The same can not be said of street level girls, where the HIV infection rate can reach 70% in some cities.

In general - which doesn't mean there isn't a risk, but you are less likely to contract HIV as a top, so long as you don't have any abrasions or open sores on your penis.  Also using lube may reduce risk by reducing possible abrading and tearing of either persons skin or membranes.

As others mentioned that doesn't mean a top can't get chlamydia or any number of other STD's, or HIV.

Regarding oral transmission, the only case I am personally aware of where someone got HIV from oral sex was a gay guy I knew in San Diego.  He knowingly had oral sex with another man who he knew was HIV positive, and swallowed.  As he explained it to me he had a drug problem at the time, and was very depressed and (obviously) used bad judgment, and the law of averages caught him.

There is a new HIV early test out that can detect HIV as soon as one week after infection. Follow that up with a regular test in three - six months, and assuming all are negative you shouldn't have to worry.

Good luck,
TS Jamie