Your first run at 1.5 sounds like mine. Couple of ideas that helped me. First lets agree on one thing......cardio sucks. Ok, now that we have that out of the way............I always ran first thing in the morning before breakfast. It sped up my metab. and I could still eat a solid 1st meal. I wore a watch and tried to run 3min walk 30 sec so on and so on until my endurance built up......only took about 6 sessions 3x/week. I honestly lose out on my workout running before and I have nothing left after........JMO. Running after heavy squats(usually the day after, never run on workout days,JMO) was tough on the old knees so I usually jumped on the bike and rode in the lowest gear possible for 30-45 min.........just to mix it up. Worked for me........may not for you. Just my .02.

Oc