Wondering if the emotional issues that led to lower grades in the past are still around? Or is the stress mostly the result of worrying what others think/being hard on yourself because of the low grades in the past? It sounds like you might still be struggling with being kind to yourself.

I can relate to that, as I have been feeling a loss of confidence related to work recently. I know that I am intelligent, but I rarely come across that way - till others know me better.

I'm not sure what the key is. Sometimes we bite off more than we can chew and it's best to change course in order to experience success. But, the decision to change course (such as choosing a different career, or major) can feel like a failure in itself. Maybe there is also some external aspect of study (or in my case, work) that we didn't anticipate, that contributes to stress. In my case, I didn't realize that my work environment would be overstimulating.

I hope you find something that helps break the cycle of your thoughts and lets you regain confidence. Good luck on your finals, and be sure to be good to yourself over break!