What is this retrogression

the thing is that i am in USA now. i have finished all my exams have an emplyer whos all ready to file for me and the only thing i dont have is visa screen.. so can i still apply both 140 and 148 toghteher and submit the visascreen when i get it.. or if i cant apply until i get my visa screen and the quota is full then wat wud be the option..

thkns

Hi Ms Suzanne,

I am currently in the US. My employer filed my I-140, 485 and EAD (medical exam, visa screen and the attached checks) yesterday. How will retrogression affect my stay in the US? My 6 months stay is valid up to Oct 15. is approved? I understand that my Adjustment of Status will be delayed when retrogression sets in.

What will be the first document that i will expect to receive from USCIS?
Will they send it to my home address or thru my lawyer?

Is it true that I may not be able to go home until the whole process is over? In between the waiting time, can i avail of an Advance Parole or you wouldnt suggest?

thank you so much.