Do I have to sign the mediation hearing for a global settlement though I’m not happy with the outcome?

If you want to settle a case you must sing a settlement agreement. If you don't want to settle you can go to trial. Those are basically your options.

Talk to/hire an attorney TO REVIEW this nonsense BEFORE you sign away any of your rights. It'll be worth the $200-300 dollars.

Why did you sign the term sheet? Almost every plaintiff gets "buyer's remorse" after a settlement is reached, and that is a natural reaction. Do you have an attorney, and are you following his advice? Does the global settlement address unemployment benefits? You probably have the right to revoke the settlement (if it includes a release of age discrimination claims), but in my experience, any revocation is a short-sighted, highly damaging, emotional reaction, not a well-reasoned, prudent response. You will risk getting zero. You may see you options as "getting more," but in reality, the defense will move for summary judgment, and probably will not offer to settle again. Is that really what you want? Further, often various causes of action will not provide damages for "emotional distress" - that is, you are not entitled to damages for that, even if you win, in, for example, a workers' compensation case. Did you really have viable claims under all those statutes? Just because you release all possible claims does not mean you have viable claims under those statutes. If you have not had a lawyer, you should definitely get one to advise you, but if you have one, follow their advice. If you think you lost confidence in your lawyer, seek a second opinion, but based on what you've said and what the circumstances usually are, it would be folly - and quite damaging - to revoke the settlement against your lawyer's advice.

Generally no. Mediation is a voluntary attempt to see if the parties can resolve their differences with court intervention. If you prefer not to participate, you will be directed to proceed to trial.

You do not provide enough specific information to respond to your question(s). You should contact an attorney who can evaluate your overall situation and inform you about your rights under the applicable law(s). Settlements are good in most cases because you have certainty about a potentially unknown outcome or loss of your case so that you might get nothing.