Some good tips by the NY Times on what to do when you think you're about to get fired. Especially good: think about requesting a neutral reference (dates of employment and salary only) and get all the personal stuff off your work computer (if any, why is it on there?). Also, take good notes with names and dates about potentially discriminatory acts, and call your lawyer.
See this link: https://nyti.ms/2Rr4Ady?smid=nytcore-ios-share