The problem with Priest wasn't really healing, but the amount of cards that discover cards that discover cards etc.
You just ran into more deffensive version of Warlock that probably didn't even have that many threats, except for giants and maybe 6/6 taunt. If you practice against it it's actually a decent matchup for Rogue (I'm assuming you play Quest or Tempo, not Garrote). I play Quest Rogue and I like this matchup, if you need any tips feel free to ask :)
Remember, Warlock usually needs to pick between healing, removing your board or developing the quest. It's your job to make this choice as difficult as possible!