Break is making vibrating noise

When i take my truck out first thing in the morning and come to my first stop, i hear a vibration sound and weird noise coning from the brakes. The brake pedal is hard to press and usually im unable to come to a full stop. Once it happens once it usually stops for the rest of the day. This morning though, it did it when leaving my house, and did it again after about 10min of driving. First time it happened i thought it was my cell phone vibrating in the cup holder, its the same sound. But now its getting worse and im getting a bit scared it might happen when i really need to brake and it wont... Anyone know what this could maybe be?! Thanks

 

Sounds like the ABS. I would get it checked out ASAP.