I think you'll find that the Doc, is saying that if you continue to back $1.25 Favourites (which I know you do). You are going to need to get 80% SR JUST to break even.
Going by your post, your bet was a BIG one for you. What would of happened if you lost (I know it didn't)? You should be betting to some kind of staking plan, not just trying to CHASE your losses, because that's what you did. Just read you post Title and think about the consequences of a loss. You should never put yourself in that position.

I've mentioned it before, but try looking for value.

Just for the record.
I have backed Houston vs Dallas (+6.5pts) @ $2.02

so hopefully Dallas win by 2 and we both win