Immunity to this drug class isn't really something that happens. What's more likely going on is your body adjusted last time around and hasn't fully reset yet. After stopping for two months the receptors sit somewhere between fresh and fully adapted, so give it three to four weeks after starting again before expecting to feel much of anything. And that eight pound bounce back is mostly fluid and stored glycogen returning, not genuine fat regain, so don't count that against yourself. I'd hold at 1mg for a solid month before calling it a bust. How far along are you since restarting?