Did you ask them about it? ('Is that standard procedure? Why did the FS change their mind?'

Personally I would choose a clinic I trusted.
The specialist said I was fine to start the cycle. She went away to get some paperwork. Came back and said there were 30 patients already starting a cycle this month. I said I couldn't skip a cycle. She went away to talk to someone. Came back after 5 minutes and said that my progesterone level was too high (at 7) and I had to get more tests and start on Monday. But she said I was fine to start straightaway 5 minutes ago. I asked why has she changed her mind. She just kept saying my progesterone level was too high even though she never mentioned it before. I told her it will be day 5 of my period. She looked surprised but then keep repeating the same speech. So now that's the only option I have.