Please don't worry, this is statistically extremely unlikely to be anything sinister.
Lenzetto is very weak and you more likely than not have urogenital atrophy, which can cause bleeding from the very thin skin which splits and tears easily.
This could be exacerbated by having a urine infection - increased frequency and wiping, it could be blood in the urine due to the infection and not coming from your vagina or uterus at all, or the antibiotics could have changed the absorption or metabolism of your hormone therapy.
In the short term I would try taking the progesterone orally to give the urogenital area a break, get some vaginal estrogen and consider increasing the lenzetto to 3 sprays.
If the bleeding persists after the UTI has cleared and despite adequate estrogenisation of the vagina, then I would see your GP.
It would also probably be worth trying to see a menopause specialist to optimise your ongoing care.
