Hi and welcome to MM NJJ
You poor thing - it's awful when doctors don't explain things properly and just leave you worrying without fully understanding the full picture.
I assume you have had a scan due to an unexplained bleed? If you are 4 years post meno then a vaginal bleed does need to be investigated - however you don't tell us how old you are? if you are still in your early 50s then sometimes the ovaries can give a final gasp and produce some oestrogen that could cause this bleed. I'm certainly not an expert but I think a 5mm thickness is unusual in post meno??!!! If, however, the bleed is something more serious then early detection and treatment is very wise - you should get results from the tests soon and, if required, treatment can be set in progress. There are many reasons why one gets a bleed so don't expect the worst - however, I do understand that you may be thinking the worst.
As to the UTI - when they test your urine sample, does it come back from the lab showing infection? Often when meno hits, we women get UTI symptoms without infection (there may be trace blood present) and these UTI symptoms are urogenital atrophy that needs treatment with local oestrogen and vaginal moisturiser.
At one time the burning urethra and urge to pee was so bad I was peeing blood and I got very frightened. I had a cystoscopy which showed my bladder was fine - I was told it was atrophy and I needed to keep using local oestrogen - this local oestrogen really helps to keep things comfortable and I will probably need to use this for the rest of my life.
Antibiotics won't help I'm afraid unless there actually is infection present. Do ask your GP if the tests showed infection - once your pep results came back as all clear, I would actually ask the GP to prescribe Vagifem local oestrogen as this will help keep the whole urogenital area healthy. In the mean time do buy some SYLK vaginal moisturiser and use every day to help to keep things comfortable and soothed - you can get this online.
It's good you are getting tested as this is wise and necessary. Hopefully all will be made clear soon - but in the mean time, try to relax more, eat well, get out for some brisk walks and be reassured that you are doing all the right things to ensure you stay healthy for the long term.
Keep us posted DG x