#1 the only parasite you can get from rimming would be worms like pin,round,hook,etc which are is easily diagnosed just put a piece of DBL sided tape next to the anus when you go to bed because they come out at night to lay eggs and will be trapped, just remember they can look different and be small. They're 3x more more common than head lice and are much more likely to be gotten from kids who get the eggs under their fingernails and can be spread by contact or airborn and are microscopic.. once confirmed go to Dr and they will give u a rx
Unless you have travelled to a tropical destination you probably are safe as far as weird scary parasites.
Please list as many symptoms as you can. I have another idea of what is a more likely cause of your fatigue.
It's patently absurd to think that these symptoms were caused by a single encounter 3 years ago, and it's offensive to assume that transgender women inherently are more dangerous to have sex with than anyone else.