hey karimah,
you're definitely not alone!!!
the thing about being in the car, and at stoplights, or even when driving, --i've had similar thoughts many times....of course, i never did it, but thought, what if i don't break right now, instead just keep my foot on the gas pedal?!!
i've learned to keep my mind on other things, and to play my favorite music while i drive, so now, i hardly have these thoughts anymore..
they say these are very common by the way. dont' fret too much about them, seriously!!!!! take good care of yourself!!!!!!!