I'm in a very similar boat.. I've gained and lost the same few lbs, partly because I can't find my motivation and partly because it seems to slow at each stone bracket which is where I am now and i get fed up! Planning on picking up my exercise again as have a week off work this week in the hope that will kick start things again.
What's helped me is looking back at photos of when I was bigger (I've lost 2 stone and the difference is crazy!) and I don't want to go back there. It made me want to cry. Maybe something like that will help you? Good luck, I know you'll find your thing that gets you losing again x