Last few months I've had a couple of illnesses which mimicked some of my PCS symptoms. They were pretty scary cos at times it felt like a major relapse. Of course it's possible to get normal headaches or other illnesses when you have PCS, it's hardly going to make you immune to them is it?

You just have to take things as they come and let it happen. If you have a 'normal' headache you should be resting and drinking a lot of fluids, which is the same as you should be doing if it is a PCS headache, so as long as you don't get too stressed about it it doesn't really matter.