You have poor circulation like myself. One hours of aerobic exercise 3 times per week will help this plus improve the oxygen supply to your body cells(which is why u are weak). I also take Cayenne(Capsicum) tablets which is a natural means of improving circulation and it has worked for me! All the best!
Yeah it's hard to say but I would also say see your doc. It sounds like you probably have poor circulation. If you don't every really exercise that could help the circulation. But for sure see your DOCTOR.
It's so hard to say what may be going on. The best thing to do is see your Dr for a checkup.