I become alert in my sleep and then I notice I can't move, open my eyes, speak, or even breathe for a while. I almost pass out. Whats wrong with me?

You are still asleep. And are dreaming. Don't worry about it.
Sleep paralysis . What you are describing is a phenonema called "sleep paralysis" that generally occurs while waking up from sleep. Sleep paralysis is seen with extreme sleep debt, that is not getting enough quality sleep and with narcolepsy. Not enough sleep can come from lifestyle, illness or sleep disorders such as obstructive sleep apnea. Narcolepsy is a disorder where people have trouble staying awake.