Why would I lose water pressure in my house for several months after running the outside faucets?
that when we use the water outside it pulls some of the water from the 
  pipes in the house and puts bubbles in them.


I'm not quite seeing the bizarre method by which this would take a month to clear out, but I think I see at least part of the problem - probably something like a defective vacuum breaker on the exterior faucet is somehow doing exactly that - putting air in your pipes. 

If that air remains trapped for some reason (weird configuration of the pipes) it could result in a situation where you have a section of pipe with a trapped air bubble and a little bit of water running in it. This is not particularly common, in my experience - normally air in the pipes comes very noisily out the faucet the first time you turn it on - but to get your symptoms I have to speculate that somehow it stays trapped, and then over the course of a month of using the water with lousy water pressure, it's gradually dissolving the air into the water and carrying it out of the pipe, until finally the bubble is gone and you get normal pressure.

Mind you, it's also bizarre enough that it could be some other thing, but this would fit the air bubbles heard and the month-long recovery. And it may well mean that there is something else wrong for it to be able to happen in the first place, but I can't quite picture what that might be.

You might try removing an aerator on one of your faucets (reduces the restriction there, will let the water run faster) to see if that will help "burp" the air out faster. i.e., you'd see &amp; hear bubbles coming out of the faucet if it was working - don't just leave it off for a month - if it doesn't work in a few minutes, it's not going to help.