I shook the mead during fermentation and I'm concerned that i may have hurt the yeast, causing it to produce less alcohol. Could this happen, or am i over thinking it?
No it wont. In fact it can break up yeast floculation and aid fermentation.
There is risk of oxidation if much alcohol has been produced when it was shook. But the c02 in headspace should minimize it.
I once fermented a 5 gal 1.086 apple wine to 0.992 in a couple days on a stirpate to completely deny the yeast floculation.
The answer to your question is really dependent on which stage of the fermentation your mead was in. If it was shaken during the aerobic phase... perfect. The yeast require oxygen to divide cells and prepare for active fermentation. If the shaking occurred during the rapid/active ferment then you are still OK as shaking here won't destroy any yeast nor will any oxidation have effect. The only time adding oxygen to your mead is bad would be after degassing. It would take quite a bit and deliberate methods as well.
Yeast are durable little guys and there's no way to hurt them short of extreme temps and sanitizing products.
Now as for the whole oxidizing the mead fear is related to you... This would only affect your mead in long term storage life. More than 5-8 years before any results would be noticed.