I thought I'd put my two cents in, since I've been in the same boat.
I was a mechanical undergrad at Texas A&M, and it was torture, especially the first couple years. The classes got a bit more interesting in upper level, especially design and ProE were awesome. I must admit that many times my buddies and I thought about quitting, but I'm SO glad that we gritted it out and finished it off.
Incidentally, I'm not a "math person". I did poorly in Math classes, but did well analytically in applications, so don't let advanced calculus stop you.
Mechanical has been a great foundation for my career. It's nice and broad, so that you could diversify down a large number of career paths postgrad.
I worked postgrad as a mech design engineer for a contract industrial design company in Plano, TX. It was a great job, with a large number of diverse projects that really made me develop as an engineer. The downside to consulting I learned when I was laid off due to the telecom slump last Spring!
Now I'm a Biomedical Masters student, again at A&M, and although I look with distaste back at my undergrad (and laugh at my poor little brother, who's an ME junior!), it was so worth it.
Hope this helps.