OPT expires in two months and travelled to India

My OPT expires in December 2016 and I had to come to India because of some issues. I am on OPT extension. Also, I have F1 visa stamping till 2019. What are the options for me to come back to US? Is it possible to come back to US within a week and convert to F1 visa from US? If I apply to any university, should I go for visa stamping again? What questions will be asked at the port of entry?

You can enter USA, if you have a valid job and a letter from your employer stating that you work for them with you manager’s /HR contact details. This has to be with your company letter head. Prove that you have a job and you are returning to USA to continue it.

If you are working as a consultant for a client, it would have to be both employer and client letter.