Cardio is Causing Me Panic

Today I went to the gym and was quite embarrassed to do only 5 minutes on the elliptical, then leave. My heart rate and breathing were scaring me, even though I wasn't going very fast. When I say "scaring me," I mean I could feel a panic attack coming on if I didn't stop. For one thing, I am confused about my target heart rate. Another, I have exertion-induced asthma. Any time my heart gets pumping and my lungs start working, I worry I'll have an asthma attack, which sometimes triggers a panic attack. It's for real embarrassing. I'm afraid of moving. Ugh.
In my mind, I'm going to the gym to complete these intense fat-burning workouts. But the reality is, I've got to get used to using my body again. Reminder: I was bed-ridden for 6 months. I've forgotten how to breathe properly. My muscles aren't used to doing ANYTHING.
I have a few ideas on how to proceed:
1. Give up now. (Ain't gonna happen, Hope)
2. Talk to a gym employee about helping me figure out the heart rate business.
3. Skip aerobics at the gym for now and get my walks in around the neighborhood, since that doesn't seem to freak me out. Use the gym for circuit machines.
4. Instead of thinking of this as a fitness routine, think of it instead as physical therapy, like I'd do in a rehab facility. Take this project away from Harley and give it to Tara. (I have a handful of persona's that serve various purposes. Harley is my inner bitch. She's the one who gives Hope a talking to when Hope is being lazy and making excuses. Harley is a good motivator, but she can be a bit harsh. Tara is the compassionate, wise, nurturing one. She can gently but firmly help me rehab myself until I'm ready for the gung ho Harley to resume cracking the whip.)
I'll try some of these alternative approaches this coming week and see if I can gain a sense of control over my physical efforts.
Fortunately, the nutrition portion of Operation Healthy Hope is going better. I'm doing one Coke a day but otherwise severely limiting carbs. I'm making sure I eat three times a day.
Oh, my initial weigh in is 210 pounds.