Replying to Anyone else...?

Does anyone else ever experience a really odd sensation after stretching? Usually I get it after sitting for a while, and i get up, hold my breath and stretch my whole body and then i get very lightheaded and have to sit and pretty much get really fucked up for about 30 seconds or so. I figure its just a headrush or whatever, but it is much stronger than your usual being lightheaded. Its such a weird feeling i cant even describe it, its like being crazy for half a minute, you cant think straight and your thoughts cant be controlled, and as soon as it comes its gone. I know everyone experiences a headrush or rush of blood to the head after sitting for a while, but this is much stronger and weirder.