H1B, H4 Visa

I switched from Employer A to Employer B with receipt of acknowledgement of H1B petition filing from company B and my new employer had applied for H1B transfer and extension.My existing work permit was valid till 16th April 2018 while new visa was in premium processing mode. I received RFE on "Not a specialty occupation last month which was responded back and now I have received denial from USCIS. My employer B has given me two option now - 1- Appeal the decision as my skills are niche skills and the appeal decision which may take 6-12 months. 2- Go back to home country and wait 6 months as cooling period and my employer B will apply fresh visa again.
I have my i-94 valid till 11th Aug 2019 and same is mentioned in my passport visa. During entry to US, the immigration officer wrote 16th Apr 2018 on my passport in my entry stamp as my work permit was until 16th Apr 2018. Please suggest when I will be out of status and how much time I have to look for other options. Can my employer file fresh petition with out waiting 6 months?