Further troubleshooting may be in order, but it's a good idea for us to check if there have been any outages in your area first.
In order for us to do this accurately, you'll need to provide us with a street address or intersection where you're experiencing the poor coverage.
What if there's a network problem?
Make sure that data is enabled on your account in the Device Settings as well as on your phone. If you're able to get a good data signal outside but not indoors, then it may be building materials or the building's Wi-Fi network interfering with the signal.
Can I improve my reception in specific locations?
If you get poor reception at home or at another specific location, you can try using a signal booster.