What high-paying job can i do with these a levels?

There are a few problems with your question. Firstly, " I'd like to have a good income of course and also enjoy what I'm doing.", well, doh, who wouldn't. However, it doesn't quite work like that.

Secondly, "I just like to have a future planned out for myself." you are likely to be far more attractive to employers if you are the kind of person who can adapt; have goals is fine but it's more important to cope when things don't go to plan.

If you were predicted AAA I would still have doubts about your working in the three fields you mention, you don't actually seem to have any real interest in them save the high secure income. You should, I believe, try to work out what degree will give you most interest and will be willing to work hardest at, which is the most interesting of your A levels for example? That should be a starting point if you don't have a strong idea of a career.

The good income will come (probably) to someone who is interesting company, interested in their work, willing to work hard and do silly hours maybe while you are unattached, has good literacy and numerical skills and can be flexible.

working in your our local supermarket selling cheese or fish,,

you will have to go to university or college first before you can become a vet or a dentist

go to uni it will open you up so many more oppertunites