Just a quick background.
Been on paleo for almost 5 weeks. lost 5 lbs
30 yrs old
5'1.5
My BMI is 25.3

I am pretty out of shape in a sense that I am always out of breath walking up stairs, cant do a single regular push up, forget about pull ups, and my max on a single dumbbell that I could do reps on without a problem is 5lbs. Never been athletic and never been very good at working out.

I started by walking around the block once... then eventually was able to walk for an hour. Later I followed the p90x for a few weeks until I noticed it was not working for me, and tried insanity for a few weeks which I liked. I could not finish one single session, but I tried as much as I could. After my surgery I was back at square one and started my walks on the treadmill since starting up paleo.

I recently started doing dumbbell exercises (with my 5lbs) with sit ups while watching tv if I am too tired for my treadmill. The next day I'll walk/light jog followed by some dumbbells and sit ups. I do sweat a lot but I am wondering if these "not so strenuous exercises" are a waste of time? I am thinking any exercise is better than none until I gain more strength and stamina...?

Once I feel better while exercising, I'd like to try Callanetics (thanks avelin) or Insanity again.

google simplefit.org and start on level 1 (modify pullups if needed).

Thanks but the problem is, I cannot do a single pull up. The push ups I can do it lady style.