Please read and help me overcome this

I applied for medicine twice (took two gap years) after my BSc didn’t get in. I then started MSc last year. During MSc, the whole year I have been really depressed and wasn’t able to get anything done. I wasn’t able to submit essay after term 1 and the exams I did I did poor grades. So I had to attend a meeting with faculty lead who advised me to interpret studies as he said that he can see me failing the whole course so it’s not good for me to continue but I really didn’t want to interpret as I wanted to stay busy and wanted to stay away from my family bcz they put me depression.
So I asked the uni that can I switch to part time from full time as that will allow me more time to complete the course and I will also be engaged with studies.

They allowed it but at the end of term 2 which means I attended all teaching for term 2 and I also completed some online assessments. But since they allowed me I decided to go part time.

Then back in July I got an offer to study medicine (I was first rejected but then got through waiting list) so I had no idea that I will get into medicine.

Now that I have to start medicine this Sep means I can’t continue my MSc so I decided to exit with an interim qualification however, the university is saying that they can only allow me to exit with a PG certificate and not PG diploma as If I submit the remaining assessments now to get a PG diploma it would be unfair to other students.

I am just so much in regret I don’t know how to overcome

One way I’m regretting is that if I wasn’t in the condition to complete the full MSc why didn’t I apply for a PG certificate at first instance bcz as I was trucking to complete the full MSc for the whole year And I have been struggling I have been so depressed the whole year however if I wasn’t doing it as an MSc I would have had plenty of time to look after myself.

And second is that I was overthinking each and every assessment so like for essays I was spending so much time into the details thinking I won’t get a good grade if I don’t but then later came to know that other students on my course actually got really average grades (around 50-60) in those assessments I was overthinking and now I’m regretting that if I’d not have been overthinking them I’d have at least completed them. And I attended all the teaching and even wrote a full lab book (which the uni is not accepting now as they are saying it’s not valid to be submitted now) but I won’t be getting anything for it so it’s all gone to wasted.

Why this happened to me my whole year was extremely upset with lots of bad luck. How can I stop regretting such a big mistake

I applied for medicine twice (took two gap years) after my BSc didn’t get in.
...
Then back in July I got an offer to study medicine (I was first rejected but then got through waiting list)...