I started out really slow as well, takes time to learn exactly what your personal bodies real needs and wants are and how hard you can push before things start to give. We are all different in subtle ways.
Tweak and tailor your plan until you are happy with the results.
Don't ever expect great losses though, if they happen fine but don't rely on them to be there.
Round two !
You can be a warrior or you can be a slave.
When the body is pushed beyond limits, rely on your heart to survive.