Lightbrite- thank you for sharing your perspective. It honestly never occurred to me that tznius could be so difficult for someone who is as much of a “bas aliya” as you seem to be.
I know you said you don’t want solutions, but I would like to point out that the idea that dressing tzniusly causes Vitamin D deficiencies is a very controversial one. My brother who is not Frum and is a medical school graduate said that it is ridiculous and you can get enough Vitamin D from being outside for 20 minutes while dressed tzniusly. Also, my doctor who very much believes in the Vitamin D deficiency thing, told me that it is very controversial and most of her colleagues disagree with her on it. My brother explained that the reason why so many people are supposedly lacking Vitamin D nowadays is because they raised the amount of Vitamin D that they decided people should have, but there was no real reason for that.
In terms of your other reasons, it is hard for me to understand why it is so difficult, but I don’t have to understand. I don’t find it so difficult; you do. I guess different people find different things difficult.
You said that you don’t want solutions, and I am not sure that I have any anyhow. You are right that Hashem does not want us to get depressed. All I can do is to give you a bracha that you should find a way to grow in tznius without getting depressed.
I know you don’t want solutions, but maybe you should try taking small steps or setting up a reward system for yourself (or with others if that makes it easier).
You definitely sound to me like a real bas aliyah and someone who does have Yiras Shamayim and is always trying to grow, so I wish you a lot of hatzlacha and continued growth.