Dropping our barely week in ? Bad mental health

I’m doing my pgce. I’ve put serious thought into it over the course of two years and have heard all the horror stories about workload and such. I’ve transitioned from a creative bachelors and honestly it’s already overwhelming. I’ve barely started and placements don’t begin for a few more weeks and I’m up with anxiety every night. I have a few mental conditions aswell as physical and was cleared as fit to teach but also feel like an imposter because I feel so overwhelmed with anxiety and negative emotions towards the course. The staff and students are all lovely, the university is amazing I just don’t feel like I’m fit to become a teacher and it’s scary because I’ve come this far already. I also don’t want to look stupid dropping out this early. I’ve considered trying to stick to it until my placement begins so I can see if I still feel this way but my mental health is in shambles. I know I already have one degree but I feel like such a failure if I leave. For some context I have ptsd, anxiety and depression.
What’s anyone’s thoughts on this? Has anyone done something similar or thinking the same?