When does my employer coverage actually end? after 11 years as an electrician's helper

I was told my coverage ends on my last day, but the letter says the end of the month. It has been a long 3 weeks. The letter is unclear about dental and vision. What should I do about appointments?

I moved my appointments earlier while coverage was active. It saved me a bill.

Dental and vision sometimes end on a different date from medical. Mine did.