Heart rate high and weak. my heart rate is like 130 when standing. my legs feel like they're going to fall off. can a virus really do this for 3 weeks?

More going on: If this is due to a viral infection, it's not just a simple "virus". From your other symptoms: lightheadedness, off-balance, weakness, plus your high heart rate - I would be suspicious that you're dehydrated or overmedicated (?). A viral cardiomyopathy could cause these symptoms - an echocardiogram would be needed to support that dx. Meanwhile. you need more evaluation.