On my way home from work tonight. About a mile away from my house and the brake light came on. Thought nothing of it, it went out after a few seconds.

come time to turn into my driveway and I had plenty of pedal, but it took alot of effort to even gradually slow the truck down. I don't know if I could even safely drive it creeping along.

I looked under the hood and the vacuum pump still has the belt on it. Where do I go from here?

 

Sounds like the pump went bad. Or you have a serious vacuum leak.

 

Vacuum pump went bad. 45min job if you have the right tools.

 

Is that a Ford dealer item or is it available at a parts store

 

Available at part stores. You will need a power steering pulley remover to get the pulley off. You usually can rent or get a loaner puller from the parts store, or take it to them and they will pull it for you.