PTSD after seeing a dominatrix?

I honestly think this has happened to me

I really regret doin it but i feel humilated and shameful and degraded etc.

it was around 2 years ago and i dont feel ive ever recovered from it,

can anyone help or advise?

You may try to reach out to her and tell her how you feel and what's going on. Even by phone, although that can be difficult and impersonal.
Some Dominatrixes have a heart of gold, but if it was for money, she was only doing what you asked her for and you might have to schedule another appointment/date to talk to her?
Some prostitutes are best left alone, but it feels as if you need closure with this one about what happened. If it didn't end well, then skip the contact attempt.
If you choose not to have contact or if she wishes no contact with you, then you are doing the right thing by talking about it safely and anonymously here. It is the first step in healing and figuring out how, what and why it happened.
The PTSD may have there long before your date and you were trying to seek relief by having her act it out upon you. It may have backfired, but you also learned a lot about yourself from it.
When I got drunk, I did very self-destructive and regrettable things. If this applies to your situation, please take the next step.
I'm not sure of your situation, so I don't like assuming things about you. If you weren't in your right mind, then find out what you can do to keep this from reoccurring.

I hate to have to ask but do you have similar problems with "regular" sexual encounters, or was it just this single BDSM encounter?

Do you feel like it was yourself who did something wrong, or that it was she who did something wrong to you?