Unfortunately, the English language can be confusing, even more so than other languages.
"Used to" can, like you said, be used to explain something that's been changed--for example:
I used to like broccoli, but I don't anymore.
I used to like only broccoli, but now I like asparagus, as well.
I used to be afraid of snakes, but now I'm not.
I used to be afraid of snakes, but now I won't even be in the same city with one.
If you leave out the part after the comma, it generally means "but not anymore". So:
I used to be afraid of snakes. [but not anymore]
Someone may misunderstand you in this case.
You can also put emphasis on the word "used" to help someone understand the new meaning.
I used to be afraid of snakes.
Good luck!