Partner can't handle my spirals

I know that I shouldn't expect anyone to support me endlessly. My partner doesn't insult me or anything like that during my especially bad spirals, but she really needs significant alone time even during the spirals. It stings more than it should. Is not being able to "handle" your partners depression normal? Or is this a red flag I should be concerned about? The reason she says she can't handle it is because it's endlessly sad and she feels like she can't stop it and she feels useless and sad too. It hurts that she has to take alone time, but I worry I'm overreacting. Anyone have any advice on how to navigate this? It's a very new relationship and we both struggle.