I know the feeling - I was an international student too and it was nerve racking. Here are a few things to keep in mind
- You should be worried if you lied on your resume - for example wrong school, fabricated work experience, GPA, wrong dates etc.
- If you did not lie you absolutely do not have to worry - the point of the check is not to rescind your offer but to verify your information. I would reach out to HR, ask if there is any way you can help speed up the process. For some things (police verification from home country) you cannot, for others (hard to verify work info) you can by offering whatever information you might have (e.g., pay stubs, offer letter, contact info etc.)
You wil be fine - it just takes time