No Friends - Need a Best Man

The headline for this post kind of sums up the situation nicely. I have zero friends and zero best man.


Actually it's not entirely true. My best friend who is a woman, moved to Australia 6 years ago and cannot afford to come or take time off work (she's a teacher with strict rules on annual leave) to come from Australia to the UK for the wedding.
I am 38 years old, I haven't spoken to anyone I went to school or college with in decades. And I haven't spoken to anyone I went to uni with since the day I returned my graduation robes.
I recently got a diagnosis for ADHD and Aspbergers, which explains why I have struggled to make and maintain relationships.
I have my family coming to the Wedding (except for my Dad and step mother who didn't want to come and uninvited themselves, needless to say the entire family are appalled), 2 work colleagues, and a few people I play Dungeons and Dragons with. Of the above, none are Best Man material, several had no idea what my last name was until they received their Save the Dates, and not a single person (other than my mum and her partner) have ever even seen the inside of my house.
Most of my fiancé's friends I have only met once or twice, so they're a no go.
It's embarrassing as my fiancé has about 60 people coming. Close friends, University friends, family, and work friends, and my guest list is less than 10 (and declining)
I have been putting off getting engaged for 8 years and the wedding for another 2 because I am frankly embarrassed that I will be stood at the front of the church, by myself, surrounded predominantly by strangers, and having to spend a day celebrating with strangers and having my photo taken (which I hate more than anything in the entire world), dancing (which is on par with having my photo taken), whilst trying to pretend that the entire thing isn't uncomfortable, embarrassing and outright depressing.
Whenever my fiancé has friends and family around, I busy myself with hosting, cooking, cleaning, making drinks, and dissolving into the background.
At my own wedding I can't do any of this, and I don't even have a friend to cling onto.
This is the first time I have said this, but felt that I needed to reach out for advice. The wedding is in July and I don't know what to do. At this point I am tempted to just forego having a Best Man and muddle through the day.