My guess is it wasn't well caed for at the nursery and you're now seing the results of that.... Rosemary can be very unforgiving of drought. Having said that, it doesn't like wet feet either.

Ok thank you.

Is it indoors or out? Rosemary is not a houseplant and rarely does well being grown indoors, even for the short spells it is brought in for winter in colder climates.

And if grown in a container, it needs a very fast draining soil...something like a cactus and succulents mix. Regular potting soil is too moisture retentive. Full sun and only enough water to keep alive.

I'd suspect that most of what you are seeing is due to too much water. Rosemary is far less tolerant of that than it is for drought or dry conditions.

I will try re-playing it in a bigger pot with cactus mix and putting it outside! Thank you very much.

TO much water