why do I feel sick after I eat?

Last Sunday morning I woke up with a stuffy nose and my throat in pain. I felt like crap. I couldn't get to the doctor until Monday and they told me I have sinus problems. Basically the typical cold. I have been taking medicine and it has gotten better since then, but my voice is now constantly hoarse, and I can hardly eat anything. i haven't eaten much and when I do I get full super quick. my body is constantly exhausted and when I walk my heart races. It's also sore around my ribs. I just wanna know if maybe the dr was wrong and maybe it's something more? and why do I feel so sickly feeling after I eat??