Long term effects of multiple burnouts

I've noticed some sort of pattern where my energy levels are concerned.

I've come back from a 3rd burnout recently. It took 2 years to recover. It was slow and often frustrating.

In the past several months I've noticed that my energy level plummets for days at a time, usually after a couple days of busy activity (ex. Canning tomatoes for 3 days, or a weekend of my husband and me babysitting our 5 year old grandson).

I'm wondering if this would be a long term effect of those burnouts. I've been told that you don't necessarily recover 100% after a burnout, and after 3 probably much less than that.

This makes regular exercise a challenge, but I'm adapting. I know better than to push myself past the fatigue.

I've had blood work done and everything is fine.

It's just very frustrating cos I never know when I'm going to wake up exhausted or not. Some weeks I can do a lot and keep going. Other weeks, no.

Because of this I haven't completed a program or even a 2 week challenge in quite awhile. It makes it difficult to stay motivated.