Is a fast heart rate bad when your sick?

I've been having my heart rate spike up while I've been sick with strep throat. Its made it a little hard to breath sometimes and I've been getting dizzy and light headed. I've been to my doctor's twice already for this but hes been more focused on the strep throat. This has been going on for 10 days now along with nausea and some stomach pain. Should I go to the hospital or should I wait and try to get back into my doctor's office again? Am i over reacting?