It does sound like hypomania leading to exhaustion. A lot of times, getting some rest, having -food- and coffee + a cigarette for me would restore me to the excited optimistic state. It's tricky w. bipolar states that aren't bipolar I because you don't want to crash into deep depression but the hypomania turns more mixed/negative/anxious when your body/brain are still moving quickly but there's physical exhaustion and lack of energy/food. I'd been able to stay in a mostly positive/energetic mood for years at a time in my early twenties and for around 10 years from ages 26-36. It seemed for a while that if what I had was hypomania, it was within a normal/healthy range and didn't do anything destructive (I still only had one "episode" that exhausted me) and I could keep things good with coffee and knowing that if I felt down or tired for a few hours or a day that eventually, things would perk up again which they always did.

I'm only having issues now cause I had insomnia that led to an exhausted crash this summer leading to med changes from the 10 mg Lexapro I was put on 10 years ago not for depression but for chronic migraine. They assessed my episode to have been hypomanic and changed my dx to "moderate mixed BP" and the med changes as well as dx have had me over examining myself and wondering if things could be fundamentally okay. I'm pretty sure had that not happened, I would be sailing by just fine still on 10 mg without feeling so vigilant and imperiled.

With how bad I felt at a few points in my life (age 16 and age 24), it seems miraculous I was okay for so long but it definitely can happen and hopefully will happen again.