bridge tap and internet connection?
The bridge tap basically just means that you have your DSL modem connected to a pair of phone wires that also branches off to (probably) other jacks in your home. All of those jacks are "bridged" together. This could literally be crimped or twisted connections inside your walls, or you might have a wiring closet with more structure, such as all the wires screwed down to posts on a bus.  This is presuming that you're not on a party line and don't have law enforcement or a nosy neighbor physically tapping your phone line (humor?).

Have you recently plugged anything else into any other phone jacks in your home? If you have, then unplug it and see if your performance improves.

Even without other devices plugged into the extension jacks, a "bridge tap" can cause reflections echoing around on the wires which can interfere with the performance of your DSL modem.

What they're really telling you to do is to have a single, unbranched, dedicated phone line for your DSL modem (2 twisted wires technically, but I'd just think of it as a single thin phone cable).

An electrician or knowledgeable friend could help you with this. This is low-voltage, so the installer doesn't really have to be a licensed electrician unless your locality requires it.