Too late now, but who you mail a tax return you should use a mailing service that will track it like UPS or certified mail so you know the IRS got it.
When you mail your tax return, wait about 4 weeks and then check the IRS site:
To track your Federal refund:
https://www.irs.gov/refunds
To track your state refund:
https://ttlc.intuit.com/questions/1899433
On the IRS site you are also offered the use of an app called IRS2Go