My ex-boyfriend had it about 15 years ago, but it took the docs 2 years or so to diagnose it.
They first told him to pull himself together and stop being a wimp, basically. Then they decided he had ME. Dont know how they finally worked out that it was Lyme, but once they did, and treated him, he recovered. Although even now (or when i last saw him) he had a very low exhaustion threshold (if there is such a thing!)... once he got tired, he would go downhill fast and there was no 'second wind'.