MacBook Pro, Solid SIL, running hot, won't wake from sleep

My MacBook Pro recently has been behaving oddly. When I open the lid to wake it from sleep, the screen is black and the sleep light (SIL) is solid. I have to hard restart it every time. Then I took it out of my bag, it was very hot, but had been sleeping. It still does the black screen and solid light, and the fan was running full blast, while it was asleep. Any ideas of what may be causing this issue?

Cheers,

Adam