Lost emails

I installed eM Client about 4 months ago and for the most part it works fine but today I have lost access to several hundred, probably several thousand emails. They just disapeared from inboxes and folders. This happened once before soon after install and I decided I had made a mistake but this time I was checking emails, left the room for an hour and when I came back they were gone. Possibly they have been archived somewhere but I didnt ask that to happen and I can’t find them anywhere. The emails in question are from a gmail account and they are still there on the gmail reader so they haven’t been deleted. Hoping someone can help with this. idp