This is normal, don't worry. Sometimes it takes your banking institution a day or two actually process your refund into your account. You can check with your banking institution to see if they have received it.
If you still do not receive it in a timely manner help with contacting the IRS has been provided below.
https://ttlc.intuit.com/community/refund-status/help/what-if-my-irs-refund-is-taking-longer-than-21-days/00/26080