Diziness and lightheaded when talking.

Hi. I'm an actor, singer, and teacher and I'm about to open up a musical here in a couple of days. I had a cold a little less than a week ago, and developed laryngitis as a result. I had to use it a little bit, but tried my best to be on vocal rest as I could, and I tried everything I could to make it recover quicker (eating apples, drinking warm tea with honey and lemon, using a humidifier when I went to bed). Now, my voice has mostly come back, but there is a bit of pain in the back of my throat, and whenever I talk or sing, I start getting lightheaded and dizzy if I go for more than a couple of minutes. I'm not sure if this is still due to the lasting effects of the cold, or if it developed from something more. I don't necessarily want to see a doctor, due to the cost, but I can if there's a need. Thanks for your time.