I have come to believe that, in order for deep change to occur, sometimes a breakdown is necessary for the breakthrough to occur. Why? Because we have to learn how to let go of our preconceived notions - and this, invariably, leads to a "breakdown" of sorts.
When we begin a new way of living, and start to build new patterns, our body and mind first say "But that's the way we've always done things, so let's go back to that. It's comfortable." The body and mind want to stay comfortable. They want to keep the status quo. Change is uncomfortable. It's painful.
If we persist in trying to build new habits, there comes a saturation point where our body and mind have to let go of our old ways of being and this is when the body has a "breakdown." Sometimes it is a physical thing. Sometimes, our mind says, firstly, "I can't handle this. It just doesn't make sense." It causes an emotional or mental collapse.
So if you're going through a rough time because you are making changes, and you're feeling like you're at your breaking point, Don't Stop. Keep doing what you're doing. Because on the other side of your breakdown is a breakthrough.