I have this weird feeling when i get up from just being chilling?

Im 16 and a guy and i have noticed that when i get up from being playing videogames or anything else that doesnt require much movement, like just being sitting down listening to music for about 30 minutes or more and then i get up and start walking i get this weird feeling like i think is blood traveling throughout my body and losing strength ( almost not being able to stand up, losing my vision ( seeing like stars in many colors ) all of this for about 3 seconds and then feeling normal again. And all of this happening again the next time i am in similar condidions. It doenst happen at school though, since im ussually very active in there. Does somebody else have a similar experience? Should i see a doctor or is this normal?