The healthiest thing to do, if you can stay calm and non passive agressive is to just ask her, privately. It doesn't have to be mean or confrontational, just that you noticed her sighing and rolling eyes while you were talking and if it meant she's tired of hearing about your problems. - Or if she feels like you've ever given a belittling response to her problems like that. Open a discussion. Then you'd have a better idea if she's a potential friend or toxic.

There is a possibility that you misinterpreted, or that she is so caught up in her own hell that she doesn't see how she's sighing during your turn to talk, that you feel invalidated.

What if she's sighing *along* with you because she thinks you share the same dx, and it's like, "oh lovely life another of us is hit with depression." Maybe it's triggering for her, who knows unless you talk about it.

When I was younger, I was told at work that I was sighing a lot - I was shocked, I really didn't even realize I was doing it and that it was making me look like a bad attitude problem. But I was doing it and it was annoying the other girls - my cheeks burned - but at least I knew and was able to change that.

You obviously have many options of how to address the situation.