Please help.

I had H4 stamped and travelled to US in 2016. Then i got H1B (from 2017 till june, 2018) and changed status. Got H1B visa stamped too in India. Now project is over and I'm being terminated. My husband still hold H1B valid.

If i dont find new project/emploer in 60 days grace period,

1. In case i apply for status change. Is applying before 60 days grace period is fine or i must have changed status approved from H1B to H4 inside 60 days grace period window ?

2. Is my old H4 ( end date 2019) still valid? US embassy didnt marked as cancelled in my passport during H1 stamping. If H4 still valid, i can go to mexico and enter in H4 to US again ?

Please help. Thanks in advance.