Maybe TSR have deluded you. People on here seem to be far removed from reality.
All this A-level > degree stigma is absurd and really needs to stop. I assume the people with a mentality like this are those still in school/college doing their A-levels. I don't recall a grown adult ever saying 'A/O-levels/GCSEs ruined my life'.
Life really isn't as tough as you think. You're living in a country where opportunities are handed to you on a platter. It's just up to you whether you want to seize them. In your case, medicine will ALWAYS be there. Always. You can apply an infinite amount of times until probability favours you and you get a place.
Stop over-thinking the woes of life, that will frighten you. Take baby steps. Enjoy your courses, do your best and most importantly, persevere.