Good Morning OC,
It sound like you may need to slow down your work out and not get your heart rate so high. The high heart rate could be making you feel dizzy. Why don't you try again but start out nice and easy?
Can you sit down with your girlfriend and explain this to her and ask her to understand.
Take care and keep posting.
Hey, I have a hamster wheel too. I do in this case what I preach, if I notice my heart rate getting to high , or I get short of breath, I slow down. If I feel a flutter in my chest, I will just slow down and then gradually work back up.
The weights are a good idea, not that I have ever done them.
Reminder: If your on a beta blocker, it is hard to get your heart rate up to where you may want it so don't push past your limits.
Like Nike says, just do it.