I have been falsely accused of SA and it's tearing me apart [England]

Sorry for formatting. I'm on mobile & I don't typically use forums or social media.

Last year I was in a short relationship (maybe 3 months or less) which was going pretty well, honeymoon period, etc. and there were no issues whatsoever, I don't even think we ever had an argument.

By the time the honeymoon period was coming to a close and we were settling, things were still going really well. I don't know where things went wrong but she turned into a completely different person & split up with me. I respected her wishes and hoped the best for her future.

I continued to keep in contact and support her post breakup as she was beginning a destructive lifestyle of abusing drugs and I was hoping she would get better, yet each day got worse with both the drug use and the accusations.

The scenario went from "We can begin to work things out" to "I don't like how you speak to me" which somehow progressively built upto "you raped me". She gave a disgustingly detailed description of what she claims happened yet also claimed to be asleep during the entire ordeal, which she certainly was not.

The whole encounter was completely consensual and I'm still to this day mind blown at this accusation. It's almost like she genuinely believes it herself!!

I have been forwarded multiple posts slandering me online along with my image which, until I found this out, had never been posted on the internet. I prefer to stay anonymous and would never post my name or image, which makes it worse given the circumstances.

Is there any legal standpoint on this? Can I report these false allegations? All year all I've done is cry because I'm being branded a sex offender over social media which as I say I don't even use, so I don't even know everything that's being said. It's killing me inside and I feel as if I'm at the bottom of the barrel. I don't feel safe walking the streets and I would take any DNA test, lie detector, ANYTHING to prove that I didn't do anything.

She has not gone to the police about it and I know she won't because it never happened, so where do I stand on being able to challenge this? I can't stand the feeling of being accused of something so heinous anymore. Please help.

TLDR; Ex girlfriend is accusing me of SA and spreading false defamatory information on me & I'd like to know if I can contact anyone to fight this. She has not gone to the police.