I have all these symptoms myself. My blood pressure doesn't drop when I stand. I guess this has something to do with the blood being in the legs. The heart is beating fast to try to compensate because the blood is not coming back to the heart. It stays in the legs. The body is not getting enough blood pumped out or oxygen. That is why the faint, lightheaded, dizzy, tired, tackycardia. I feel like ****. I use to be happy and healthy. I was very active. I couldn't drive, go to work, or barely walk across a room three years ago. I'm a little better with being on antidepressants. They only give me energy physically. Some doctors think it's stress. I know and so does everyone else in my life there is something wrong. Now, I'm going to be getting my adrenal glands investigated. I was on Skelaxin, Ibuprofen, Mono Mac-antibiotic when this all started.