Hey Kassie,

Sounds like some good work there for your heart and wind.

I went for several weeks when I first started back to the gym where I was getting a bit of a headache when I would push too hard. Just take it easy, mine whent away, and don't have an issue anymore.

You were asking about core strenght. I'd recommend some big compound movements for weightlifting. Squats, Deadlifts, that sort of movement that really recruit a lot of the body to accomplish the move. Some good push/pull exercises for upper body like Dumbbell bench press and maybe a bent over row for the back. Certainly a whole array of things you can do, if you have a certain goal/interest, I'd be glad to help you out with my limited experience, though I'm not as experienced as some.