Other people answered your question about why NFP is better than birth control, so I'll contribute in a different way.

Birth control is allowed if it is for a medical reason, but if you are sexually active with your spouse, you should not be using it. I would recommend finding a specalist (maybe christian or Catholic). While I am not a woman, I've heard a lot about how doctors pretty much just prescribe birth control as the one stop solution for most women problems instead of fixing the actual issue.

That's a poor way to do healthcare, and I know a few women who have gone to non-birth control doctors who actually help them with their medical issue.