Hi Nichaleh, I have been in your position..and there is hope! I too can't do regular core work so I took the baby outdoors and walked and walked and walked some more..broken up into as many trips as necessary
I then discovered Jill Johnson who took my poor sick body and transformed my life. I did her tapes (now dvd's!, I am dating myself lol) Her program is called, "Oxycise", and you don't jump around and sweat buckets. I keep going back to her because she is gentle, it takes 15 min, and it works
. For people who can't workout on the floor she has her, "Easy Does It" series which you do in a chair/standing. I do 2 dvd's back to back 5 days a week, it is just my routine and I love it. If you google 'Oxycise with Jill Johnson' there is a website with all you will need to know about exercise and oxygen. There are lots of new/old Mom's who have come thru..must be a good reason!