The IRS quit processing any mailed or faxed documents around the time you probably sent your medical insurance papers. The IRS is way behind processing all tax returns and has many returns stacked up in trailers unopened. The state did not need the papers you sent the IRS so they processed your return and sent your refund without the need for anything else.
There is no way to know when the IRS will get to your return. All you can do is track the status using the IRS tracking web site: https://www.irs.gov/refunds
Here is how the IRS processes returns: https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions
