If you are asking if it is possible to apply after retaking A levels, some schools accept retakes and some do not. I'm sorry, I am not personally knowledgeable on which do or do not, but check the university websites.
AAB isn't horrible, but it would be great if you could bump that. I do think the D (or even C) in chemistry will hurt your application, and the B in bio isn't ideal, either.
Most students when applying will have 10-15 weeks+ of work experience, so I think a gap year, to allow you to do more work experience and boost your A levels (if you realistically think you can factor in both) is a wonderful idea. However be realistic here. CAN you realistically juggle both? Why do you think you did so poorly this year? Ok not committed, but how is that going to change? What is the plan? Why weren't you committed this year?