Yes, some vet schools require AAB and not AAA - although most stipulate the As have to be in chemistry and biology. Make a table of all the vet schools (not that many so won't take too long) and their courses (most are the 5 year standard but there is also some gateway/prelim 6 years, and accelerated post-grad 4 years) and all their grade and work experience requirements so you know where you stand. Nottingham supposedly don't look at predicted grades but I'd check first via call/email. Don't apply anywhere you don't meet the minimum for, including GCSEs - that is a quick rejection when there are about 10 applicants per spot with the vast majority reaching all requirements. The good thing is that apart from maybe Cambridge, most vet schools do not rate you any higher based on if you get higher grades - i.e. if their minimum is AAB, someone getting 3 A*s won't be further up the list than you. Work experience is as important as grades, if not more as that is a big part of the forms and interviews.
If you can't find four standard 5 year courses to apply to, look into the gateway courses, although some may stipulate rules like you have to be part of widening participation criteria or can't get above certain grades, and there are also very limited spots on gateway courses. As it is just predicted grades and vet school is quite a 'flashy' subject for schools to get a student in for, I'm sure you can attempt to up your predictions - offer the teacher your B is in to do extra work/tests to prove you can get an A, speak to higher up people like headteacher, get parents involved, just go all in if necessary as it is your future you're advocating for. There is the postgrad route where you could take another first degree than apply for either 4 or 5 year vet courses after, BUT obviously it is much longer, you will be doing a subject you may not be interested in for 3 years, the 4 year course is even more competitive than the 5 year and you won't get a tuition fee loan for a second degree, so essentially you'd have to pay 9.25k x 4/5 years out of pocket, so I wouldn't recommend going down that route.
If you fail to get grades necessary or don't get offers (which is very common! I didn't get any offers in my first application round and only got 1 in my second) then the best route imo is to take a gap year and reapply. In that time you can work on any missed grades, up your work experience, reflect on the last application round, and with the rest of your time do whatever you want - travel, relax, work to get some savings for uni. I know gap years aren't generally appealing to a lot of people at your age and I never intended to take one but it was a blessing in disguise. But for now, find unis you do meet all requirements for and if you can try and get AAA predicted just to open more doors while you can before worrying about 'later', good luck