Hi there and welcome! I love ajuga also, and I live in Maine, zone
4/5. I have experienced the same thing in years past, just an odd winter. I do leave the leaves on my patch now in the fall and rake off in the spring
. Last winter I lost a lot, but this year it looks good, even filling in areas that were lost last year. Yes, you should be seeing signs of it now, mine are budding and should be in full bloom in the next couple weeks. I would be surprised if you've lost the entire patch, and if there are any that have survived they will spread and multiply for next year. The stragglers may not bloom this year. Best of luck to you!