First, make sure you have the correct numbers to check your refund. Start here, with step 1, and check your refund amount on TurboTax: https://turbotax.intuit.com/tax-tools/wheres-my-refund/
The IRS started officially accepting tax returns on 01/29/2018. After acceptance, the next step is for the government to review your refund. It can take up to 21 calendar days after acceptance for the IRS to issue your refund, although most refunds go more quickly than that, while a small handful may take a bit longer.
If you are affected by the PATH Act, the IRS cannot issue refunds for people claiming the Earned Income Tax Credit (EITC) or Additional Child Tax Credit (ACTC) before mid-February 2018.
[Edited 2.11.2018 | 12:49 PM Pst]