Hey Jim! This is not uncommon! Depending on the tune, I would have some trouble remembering some of those songs from a few years ago (heck, even a few months ago). Good news is that if you've already put in the work of learning it, getting it back after a few months is kind of like riding a bike. It comes back a bit quicker.

When you've learned something, it's important to keep working on it every day if you can, using the repetition to burn it into your brain and fingers. It's also always a good idea to set aside some time every few days (or once a week) to run through all the songs you've learned just to keep them fresh.

Nerves in a jam situation are also common --- you've changed the environment you usually play in, so you're out of your comfort zone. Just keep putting yourself in those sitiuations and you'll get more and more comfortable.

Keep at it and let me know how it's going!!

Mike