It depends on how badly overstimulated you get. It's possible to overstimulate yourself to the point of severe and prolonged relapse (even with appearance of new symptoms), which is more or less what happened to me.

Still, sitting around and getting depressed isn't the greatest for recovery either. I find that I have to really strive for balance: modest stimulation for while (one sense at a time), then total rest and freedom from stimulation--but not for so long that I start getting depressed. It's a lot of trial and error for me, but I feel like I'm getting better at striking a balance.

It helps to not stimulate more than one sense at a time. Thus, if you're listening to music or the news or whatever, you can close your eyes. If you're reading, don't also listen to music. As a number of people here have posted before, multitasking is very difficult for us, and stimulating more than one sense at a time can quickly result in sensory overload and increased symptoms.

Pete

I played a car racing game on my mobile and I felt kind of giddiness afterwards. I wasn't necessarily tired or something just felt my vision was overstimulated and brain overloaded with information! I had to take a small nap before feeling fine. I don't know if this symptom can be related to the PCS or not because after mtbi I think we tend to link even normal uneasiness feelings to PCS. Correct me if I am wrong

The game might have caused you to get excited with a surge of adrenaline. We tend to be more sensitive to such surges.

Also, if you were engrossed in the game you might have stopped breathing properly, my brother gets dizzy if he concentrates on his computer too long!