So whenever I study over say 1.5 hours or do an exam I basically feel wired as if I've taken amphetamines and get lost in time. I stop getting hungry, can't sleep and when talking to someone afterwards I act pretty weird and hyperfocused.

Can someone relate to this?
Does this have any health connotations such as amphetamines?
Is there anyway to get easier into it and out of it?

For the record I've only tried amphetamines twice but have had this experience when studying long before and after I tried amphetamines.