Hello Dongdong,

Your case seems little complicated -- when USCIS approved your h1b -- did they approve it for consulate processing or just sent the approval without I-94. Usually change of status from F to H gets denied if you fail to provide the proof that you have extended your I-20 once OPT expires at the time filing H1B. in your case it seems like I-20 extension beyond expiration of OPT was not submitted at the H1B petition and USCIS might have denied the change of status and approved it for Consulate processing. It is weird that you did not get the I-20 with approved change of status.... usuall you will see on bottom right side of 797C(approval notice).

You werent supposed to work if you did not have the valid I-94 as i-94 is the one which determines your current status inside the US. in this case, you will have to get a immediate help from license immigration attorney and see what they say. Longer u stay with out valid i-94 in this country, more you can get in trouble.

Besides, do not go to foreign consulate with checking with attorney as there could be a serious effects. There are bunch of nepalese Attorneies also who can advise you in this matter. Consualte could deny your h1b petition citing that your worked and stayed in US illegaly..... you might need to file a waiver for that.

or at least try to amened the H1B as soon as again and see if you can another h1B with I-94

Thanks