Diziness and breathing issues.

Hi! I'm feeling  lazy/dizziness/sleepy while trying concentrate on my work.Though, at the same moment of time, I had breathing difficulty, where I feel fainted or flushed energy for that that.I got to say you, that I don't have a single fever,vomiting, headache or even cold(sometimes, a little, but manageable).Though, my muscles are Loosened or became softy since a few weeks.Even I can pull or press my muscles easily.Currently, I'm taking Renerve plus for vit-B12 deficit.Dont know whether it shall work or not.Please, doctors it is an utter request to you all, that I need some tips and medications as I can't afford to go outside as there were those lockdowns going on!. PS:-This breathing difficulty or laboured breathing is somehow returned to normal or fixed when I am lying somewhere or sleeping.This difficulty mainly happens when I'm sitting or standing doing my works!.Also I find a little bluriness in my vision while reading something.