Help notifications not vibrating in vibrate mode

[ttando123]

i have noticed today that while my phone is in vibrate mode none of my notifications vibrate. i have turned every "vibration" choice i know of on. i have put in silent mode via settings button at top and then to sounds and notifications and also using the left side buttons when it goes into vibrate mode and shows up on the screen and then hitting the "wheel" button. it has been working until this point. please someone help~