Removed as Co-Author for Resubmission
It is not ethical to remove you as co-author from a resubmission, if you contributed to the first submission and your contribution is still relevant in the resubmission. In that case, there seems to be a portion of the text in the resubmission that is a revised version of text that you wrote, so your contribution is indeed still relevant to the resubmission.
Do not agree to being removed from the author list. Don't let yourself be pressured to agree by an impending deadline. In most cases it is no problem to get an extension, even up to multiple weeks, on manuscript resubmission deadlines. Moreover, it should have been the lead author's responsibility to plan everything so that the deadline can be met.
If the importance of individual contributions has changed by the revision, it may indeed be appropriate to change the author order. That has to be agreed upon by all authors. The editor might also want to have approval from all authors for that change.
Start collecting evidence to support your claims. In the text from the first submission, mark which portions of the text or data have been contributed by whom. Collect earlier drafts and emails or other communication that further evidence these contributions. If you have the revised version, mark which portions in that are based on contributions you made earlier.
If the lead author does not resubmit to the same journal with you as co-author, try to keep an eye on other journals in the same area. They may just try to go to another journal with the revised version, where the editor will not be aware that the manuscript may still contain contributions of someone who's not listed as an author. If you see a publication with text based on your earlier contributions, but not listing you as an author, contact the editor with a complaint, and provide the evidence you collected.