I'm suddenly feeling much worse today than even yesterday.
Muscle fatigue, puns needles and vision is going funny.
We really don't know anything about you. It helps to query your symptoms on line - in a group. That way you can start to get an idea what might be involved.
Also it really helps to keep a journal of what you are doing, eating, drinking any meds/drugs, supplements, dosages, along with your symptoms... That might help you see a pattern when you check back through it.
Look up medications online like at drugs.com to see what side effects there are, and what other drugs, supplements, food might cause a bad interaction. Check out the site:
www.drugs.com
Realize that if you are feeling ill your body is handling a problem. Running could put a big burden on your body and your body then might not have the resources to handle this problem. Have you been exercising too much? Are you low on electrolytes?
You might try going to a different location, like outside to see if fresh air makes you feel better if you think something at your location like mold or chemical fumes are affecting you.
Make notes about how long this has been going on and try to identify anything that seems to trigger or worsen symptoms.
Have you had an exam by a doctor? They could run some tests to help identify the problem. Extreme weakness and vision changes sounds pretty serious and I'd strongly advise you get some medical testing and review.
Certain nutrient deficiencies can cause symptoms like that. How is your diet? Know that drugs and disease can deplete you of essential nutrients with very serious effects.