Your CV needs to show you can do what's required of the job you're applying for - and it needs to show it at a glance because if someone's looking through a huge pile of CVs, you're lucky if your CV will get more than 2 or 3 seconds attention on the first sift.
As most jobs have different requirements, then ideally you should shift things round a bit to emphasise the most relevant skills and experience you have. Better to do fewer well-targetted applications than splattering your details indiscriminately. I don't do a major rewrite every time - the content is still the same, but I might emphasise skill A more than skill B by putting it first and giving more detail, or vice versa, depending on what the job is looking for.
It also depends on what you want. My CV currently has my teamleader experience and training skills at the top, above the purely techy ones I have, because I want to get into a role where I do more of that, and can develop other people, rather than just cultivating the purely techy side.
So first of all, you really need to think about what you want - your post sounds a bit directionless. Legal secretary, maybe PA, maybe retrain to something else... It may well be the case that you don't have a clear direction at the moment, but other people don't need to know that, and it won't help you if they do. So think about what tasks and so on you've really enjoyed in your current and previous roles, what things you really didn't, and what things are you interested in and want to do more of in the future, because helping get more focus on that will help you focus your CV. Are there common themes? There are various tools online if you're not quite sure how to go about this, or books like What Color is my Parachute? And don't forget things you do outside of work may also give you useful experience or illustrations - if you've been involved with organising a charity event or similar.
Perhaps you will end up with a couple of core CVs - the legal secretary one, the PA one, and the one for the type of job you really want - if you work out what that is, that's the one to really invest your time in. (I have a techy CV and a teamleading CV - the latter is the one I really want, but the techy one might get me into another company with a sideways move where there will be better future opportunities. I then do also edit them for the role in question.)
Play around with white space and bullets and so on, because formatting can make a big difference to how key points jump out at you or not.
Whichever way you decide to go with your CV, you absolutely do have to tailor your covering letter/email to every individual application, because that's where you confirm the job role you're applying for (or the sort of role you're interested in if it's a speculative application), and you can emphasise particular skills or experience - "As you will see from my attached CV, I have extensive experience in ." Though I'm not sure how much attention covering letters get these days - I know with us, they stay with HR, and we just get a pile of CVs to go through. I don't know if HR use them to help filter applications. But it will at least show you are focussing your application on that role in that company (even if it is really almost the same application you've made to 4 other companies that week - you're not telling them that.)
Interviews are mainly about seeing if you'll fit in, but they're not only about that. In my field, there's also an element of assessing your technical skills, to gauge people's level of competence, because someone might be a really great fit personally, but if there are certain things they don't have the technical knowledge for, there's no point employing them, unless it's a training role. We also ask questions which will give them the opportunity to give examples of their problem solving abilities, because that's a key part of the support role, and how they might handle an upset customer or something - of course, their answers might just illustrate that they've got very good interview skills, but it is the only opportunity we really get to ask about things we're not sure of from just the CV. The fitting in is important, but it's not the only thing the interview is about.
As for the bullying, it will only come over if you let it. It's not something you're going to mention on your CV or in interview, but you'll already be aware that it can affect your confidence, so you might want to read up on some tips on assertiveness and conflict management and so on - this sort of thing can be helpful in interview in any case, particularly the assertiveness, and you can learn ways of how to present yourself as appearing more confident - sitting up straight, looking people in the eye, taking a moment to think before you start speaking, talking more slowly, and breathing more slowly and deeply (we've a tendency to speak and breathe more rapidly and shallowly when nervous.) There are things you will be able to do to battle nerves and lack of self-confidence, if you prepare yourself, and remember people will only know what you tell them, and what your let your body language show them.