I am looking for a prognosis on what I fear may be a terminal illness. With a 3.5 cGPA and a 507 MCAT, I have elected to largely apply DO this cycle. I have a strong upward trend (3.8-4.0) for the last four semesters, and one of my LORs is even from a professor who observed and was impressed by this upward trend. However, I may have thrown that all away this summer. I signed up for an summer calculus course, and it's going very poorly. I'm trying as hard as I can to turn things around but I am honestly expecting that a C is best case scenario for me. Should I to have an incredibly recent C or D on an otherwise upwardly trending trending transcript, how badly have I harmed my chances? Thank you in advance for any advice.