When I start driving I hit the brakes the antilock kicks in and makes it hard to stop the truck. After I jab the brakes a couple times the abs light kicks on and it stops doing this. What could be causing this problem?

 

You could have a faulty abs sensor or even just a dirty sensor. If it's been a while (meaning more than a few years), you might need to flush out the brake fluid and get some fresh fluid in there.
If the abs light is coming on, there is a code being stored. You need to get that code read. Unfortunately, most auto parts stores can't read abs codes, so you'll have to go to either a dealership or a competent mechanic. Otherwise, I and anyone else commenting are just taking shots in the dark.
If I were in your shoes and didn't know what the abs computer was telling me, I would start by checking all wiring, making sure the sensors are relatively clean, and flushing out all the old brake fluid.

 

Changing your brake fluid will have ZERO affect on this issue.

But Lewis was mostly right... it sounds like its a faulty wheel speed sensor. Its reporting that one of the wheels is locked up and that activates ABS. After a few stops the system realizes that the data doesn't make sense and shuts off.
(this is called a plausibility fault)

The codes will likely point you to which sensor is reporting bad data.

There is also a slight chance that the issue is in the ECU, but this seems less likely.

 

I'll take mostly right over mostly worng!

Have you figured anything out yet?