Random sleeping

Whenever my mind isn't constantly stimulated I'll pass out, no matter how many hours I sleep. I'll just very very suddenly pass out for a few seconds at a time, so it'll mostly look like im rocking back and forth. No matter what I do I cant resist it and it happens probably 20-30 times a day. A lot of the time before it happens my grip will just let go and my hand will go limp for a second. I dont have anemia and ive got a blood test for it too, is this normal?