Regarding resignation or termination

If your boss is asking the TSM in his team of 7 TSM's, who was the top most performer, there should be some reason, and you must be aware of it. It could be that you were a performer and now the sales Vs tgt performance is not good. In sales the sales performance can vary from period to period and your manager should get impatient and ask for the resignation. Another fact is that while you are in sales you should always plan in advance and achieve surplus so the in aggregate you should be yielding good performance.

You should have a heart to heart discussion with your boss and convince him that he should be patient with you and you shall take the right steps to bring the performance up. Since you do not have another job in offing you should get some time. You can submit your resume to various consultants, companies, and if you are a known performer your competitors should be happy to absorb you.

Instead of  submitting resignation with immediate effect, or facing termination, you can submit notice of resignation with effective date of resignation written in it, e.g. if your notice period is 2 months you can submit your resignation today and write the effective date of resignation 2 months from today. Within notice period you should find suitable job. You can withdraw notice of resignation before effective date of resignation.

Forced resignation can be withdrawn and protested.

If your performance is reasonable good or if the fall in performance is uniform in company or due to reasons beyond your control you should attempt to convince your superiors.

If your boss is being unreasonable with you, then you can escalate the matter by gentle representation  in writing to HR Head, Vertical head, MD etc, and this may get you relief.