Hello, had a similar experience of being treated badly for a mental health condition and then being treated worse when I complained that I had been treated badly. I am sorry that you are going through this. It is totally rubbish.
What I'm thinking:
You don't have to have 2 years' employment in a discrimination case.
It's good that the solicitor thinks that your case is good.
If you were always open about your condition from the start, your employers were put on notice that they might need to consider reasonable adjustments for your condition/ disability (if it was something that had a substantial effect on your daily life). When you then explicitly said that work was affecting your condition, they were then in a position of having a duty to consider if you a)were likely to be classified as having a disability e.g. by asking occupational health and b) what adjustments they could and should make for you to remove the substantial disadvantages that you were suffering.
Questioning if you were in the right job could be considered harassment or discrimination and certainly doesn't sound like making reasonable adjustments if it was then followed by an increase in pressure!
Will it ruin your reputation? Depends if it is public. In disability cases, if medical details are likely to be heard, you can apply for anonymity or a restricted reporting order. This would be applied for at the start and you would have a preliminary hearing to decide the issue. It would mean nothing was public or on the internet etc.
How long will it drag on for? It depends! You do the ACAS conciliation bit and then put in your ET1 claim form. They then get a month to reply with their ET3. Then there is a preliminary hearing to decide dates etc. There is then a delay of at least a few months while evidence is exchanged and witness statements are produced and exchanged. A discrimination case can be quite lengthy. If the employer does not concede disability, there may have to be a medical report produced. It may also take up time at another hearing or the start of the main one.
Now that there are no fees, the ET system is struggling to cope with demand. There can be a delay of over a year to hear cases that will last more than a couple of days, which yours probably would.
Cases are split into liability and remedy. If you won, you would hopefully have the remedy decided at the same time. However, this does not always happen and there can be a delay waiting for the remedy hearing, especially if there is a medical expert report needed if you are also claiming for personal injury as well as injury to feelings. My case took over a year from ET1 to liability hearing and then there was a delay of 7 months until the remedy hearing. If either side appeals, it delays things further, as it can be a very long wait at the appeals tribunal for cases to be heard.
That said, if you have a good case, they are likely to want to settle and quickly before they waste legal fees.
Your employer's solicitors will almost certainly demand to see your medical records if you are claiming disability discrimination and/ or personal injury. They did with me and the judge ordered them to be disclosed. You can't really refuse a judge's order if you want the case to continue. I agree with Daisy that a GP report might be a good idea as it might head off them disputing disability. If you claim personal injury, though, a GP report will not be enough and they will still want the records. You can redact anything irrelevant first. They will inevitably try to use bits against you to a point, but they will be held back from going too far by a judge and, as you disclosed your health issues from the start, there shouldn't be any need to interrogate you on small details. The records will back up your case.
I understand the destruction of your self-confidence. It is bruising. Fighting back has helped me to regain some strength at times. But you cannot guarantee how tribunals will go 100% so it is sensible to think about the damage that losing would do as opposed to the damage of doing nothing.
Daisychain is right to point you towards your household insurance. I disagree about not being able to get money back even if you win. Costs are rare in tribunals BUT possible to get if the other side behave unreasonably e.g. defending a point that the evidence makes impossible to defend. They are deemed to have been unreasonable sometimes by wasting time pretending they would win a point that you were always going to win, for example. But she is right that costs awards are unusual.
A merits assessment, like Dasiy suggests, sounds like a good plan.
I have found my experience completely stressful and draining. However, it has changed some aspects of my employer's behaviour and I am proud of that as others are not experiencing what I experienced to the same extent. It's also built some of my self-respect up again, though I have found the tribunal system less geared up for justice than I had hoped.
Good luck with whatever you decide.