I will start by saying I’m sorry you’re going through this during the holidays OP.... I know that it makes things even more difficult. Have you mentioned any of this to your therapist? Did he or she say how they felt regarding the relationship? And your depression - situational or seasonal, are you taking medication with potential side effects?
From a females perspective.... it might hurt like hell, but if you truly love her and care about her you genuinely have to let her go. You tried to tell her this months ago and she didn’t accept it because she wanted to stick it out and it wouldn’t effect her - but what about how it’s effecting you? Your feelings should be equally accounted for being that you’re depleted mentally/emotionally and could be making your depression worse... You can’t give 100% in a relationship if you’re not first 100% committed to becoming the best version of yourself first.
It seems like you’re more attracted to the idea of her than you are genuinely attracted to her. This could be from your depression or it could be the timing of things, but either way it’s clear that your relationship has become strained over this - at 7 months you shouldn’t be able to get enough of each other. You should be craving more of her not more space away from her - take this as a hint and don’t over analyze why. If you’re not ready at this time, you’re simply not ready and that’s okay, OP - you can’t force it.
Being that it is Thanksgiving.... I would assume you guys had a happy holiday together, but I question the fact that this was posted on a day that you should be very grateful for what you have. You clearly expressed your gratitude for your SO, but your overall doubts on the relationship seem to outweigh any sort of confidence in the longevity. Are you holding on out of the sense of obligation and comfortability, or because she’s the “perfect girl” that you “should be with”?