Hello Chfather, and thanks for the reply. It's good to know that other people may have the switching thing because I was afraid it was only me.
To answer your question about the length I can tell you that I don't use anything even though I was diagnosed from a neurologist in my country. The reason is that I am constantly traveling to new countries due to study and work reasons and it is harder to get diagnosed again every time to get the treatments in time for the cycle. But the only thing I do is busting and it makes the headaches less intense so I can go about my normal life.