Hey there, I think there are a universities that will take you in, regardless of your a levels. I'm not sure what subjects you did, but maybe have a look on the internet, or even UCAS, they offer great alternatives. Also remember that grades are not everything, remember C's get degrees. When looking into these alternative career pathways or courses, maybe email them, or in the application mention that you struggled due to your mental health, I'm pretty sure they will take this into account and will give you some leeway.
I'm just curious of how you got your A-level grades, did you sit them last year? Or are these you predicted grades for this years upcoming A-levels?
Let me know which of this is your current situation, obviously I'm not a professional, but having many friends who have not got their desired grades, I can tell you some of the pathways that they took.
Please also look after your mental health, Its very important for you to take care of that, cause if your mind is not at peace then your body will not be able to withstand hardships, so take some time away and do things you enjoy, you can message on this forum if you need someone to talk to.
Remember that after these hardships, you will be happy at the end!
Hopefully this helps, hope you have a good day (: