Rule #1 to winning any BG. Do Not Chase the horde, they are getting away, let them run away, they will be back and if you do not follow them you will be healed to fight another day.
Rule #2 Always fight at the flag, right on it, right there, not away like the horde want you to do, and again do not chase the horde they are pulling you away from the flag!!!
Rule #3 Healers are stationary things we try to stay behind the lines and fight, your job is to protect us by staying at the flag and not chasing the horde. We will move up as the whole raid inches forward. Priest are very limited in what they can heal with running. If we could run and use all our spells you would be healed all the time.
Just basic common sense that the Alliance and I bet some horde are just as stupid.