If you hate going really slowly up hills, then maybe you should have waited one more commercial break during that 3AM rerun of Knight Rider and called the number for The American Bartending Institute instead of jumping on the one for The US Trucking Academy. Seriously, right there on page one of the job description for "long-haul truck driver" it says "Must be able to spend long periods of time in a chair creeping slowly up hills."
There are plenty of lucrative career fields that do not involve spending long periods of time in a chair creeping slowly up hills: You could go to med school, learn to be a short order cook, get into the burgeoning day care field, or even run a meth lab in your kitchen, and none of these will involve staring at the ass end of another Peterbilt for 20 minutes at a stretch while ascending mountains at 49 miles an hour.
Should you find yourself ascending said mountain at 49 miles an hour, therefore, it shouldn't come as such a big shock that you have to suddenly swerve your truck into the left lane, which is full of cars doing 70+, in such a hurry that you can't even remember to use your turn signals.
If you can't stand going slowly up hills, maybe driving a truck just isn't for you? That'd be like getting a job as a paramedic if you can't stand the sight of blood. I'm just sayin'.