Muscle weakness?

Hello, i am NOT a fitness type of gal. But asking here since some meat eaters got under my skin (said my issue is because of veganism)..and i think here people know more than in some other subs

I have had muscle weakness for years (vegan for 5y) and at first i blamed it on low iron, and its not great but bit higher and i most likely was anemic in birth so its not a new issue. One thing is i have severe stress and anxiety but idk how that could cause this. So basically my hands go weak a few seconds after doing an activity. Like today i grated some vegetables and i was tired after some seconds. Now my arms feel weak and out of strength. Same with my legs. TMI if im riding my legs get shaky and weak. So its embarrassing. Im so tired i cant work.

I sleep enough. I eat enough. I take vit D and B12. But what am i lacking? :( my circulation is also very poor. Like cant lift arms up or legs. They go cold fast

Ive been to doctor they just told me to sleep well..