Diabetes related fatigue

Is it common for someone recently diagnosed with diabetes to have a period of extreme energy when they finally get their diabetes under control? I am trying to gather information on whether I have something else going on. I had had years of fatigue and not feeling like doing much of anything and then in March of this year had a DKA and a diabetes diagnosis. I had been stable at prediabetic levels for 15 years before that. But after coming out of the hospital and getting my blood sugar under control going from 10.9 A1C to 4.9 A1C, my energy returned to 20 year old levels (I'm 48). But after a few months, the fatigue is returning even though the A1C is staying low. I'm talking MONTHS of super energy. Is it possible that I received something while in the hospital or got some imbalance corrected that slowly is going back out of whack? Is this common among people with diabetes?