Your problem is that you are out of shape. When I was out of shape my HR would skyrocket if I tried to go anything other than slow up a hill, and at a high HR I'd quickly feel bad. Not just out of breath, but really bad, like my heart was going to explode. That's what you get when you're sedentary at age 40.
Now that I am in shape I'm a lot faster up hills and everywhere else and high heart rates are just fine.
Unless your vegetarian diet is nothing but Cheeze-its and Coke, it's ok. Don't worry about "controlling" your breathing. Let your body tell you what you need. If you're working too hard all you have to do is slow down.
I agree with the others who said that you don't need an HRM for this. Feel bad? slow down. Feel good? speed up.