I Am A Healthy Female, Though Overweight . I've Never

Question: I am a healthy female, though overweight. I've never experienced any life threatening disease or health issues. In February, I suffered the worst bout with the Flu I've ever had. It took me about 10 days to get up and around. As I started to recoup, I felt short of breath and generally exhausted. It took me over a month to get rid of the cough--that's unusual. I didn't bounce back as I normally do. In the first few days out of bed, I had no energy and, at times, experienced some light-headedness. Not to the point I felt I would faint, but it was something I noticed and told my husband about. We both assumed I was just getting over the Flu. A month or two went by and I began to feel normal again. I regained strength and the cough subsided. Then, in the last week I have started suffering the same weird 'lightheadedness'. When that comes on, I also notice a paresthesia in the top of my scalp (head) and I suffer a bit of tinnitus. Nothing overwhelming; no hearing loss or blurry vision. But, the tinnitus, the light-headedness and the paresthesia seem to happen simultaneously. I may go through an entire day (like yesterday) where I suffer none of these symptoms. However, it's back again today and I'm wondering if you have any indication of what might be the issue?