I'm sorry to hear about the situation you are in. Most people undergoing surgery have to stop HRT for a week or two beforehand so it's not unheard of. How you come off them though is important.
There can be side effects from stopping suddenly. If you are taking Spiro it may effect your blood pressure.
After being on HRT for two years I rather inadvisedly went cold turkey when I decided to stop my first transition attempt. Apart from being an emotional mess I started to lactate, not a lot of fluid but it was frequent, random and lasted for weeks.