This could be explained by regression towards the mean. When your health problems reached an extreme they were very likely to eventually get better. This might have happened regardless of any changes to your lifestyle.

https://en.wikipedia.org/wiki/Regression_toward_the_mean

It really is a very fascinating phenomenon. My friend who works as a psychologist have noticed that the most "successful" work is to always accept crisis patients immediately. If they have to queue for 2 months before getting clinical help, they have often improved by themselves, and it is therefore harder to reduce their problems further.