I live in a very hilly area, so I have to hit a lot of them whether I'm hiking in the woods or walking on the roads. There was one wooded hill that used to kill me. I would have to stop and take a drink of water and stretch out about 3 times during the climb to get to the top. But I made myself keep doing it every day. In about a week and a half to two weeks, I did the walk as usual, and made it all the way to the top without stopping. I didn't even realize it until I got up there. There's an awesome feeling of accomplishment when you tackle a big one. So keep plugging away at it. It's ok if you struggle, and it's ok if you even need to stop to gather yourself before going again. The key is sticking with it, and then the next time you'll be telling us all how getting up there was a breeze.
That great feeling is soooo worth the work.