It should be re potted to a larger well draining pot. Use a 5-1-1 potted plant mix for citrus trees.

5 parts pine bark fines
1 part perlite
1 part potting mix

Mix thoroughly and fill a 1 gallon pot most of the way. Take the tree out of its container and spread out any tangled or wrapping roots and place in the new pot. fill the pot up the rest of the way with the tree's top roots at the soil surface with a dusting cover of dirt. Water very well. I usually set the tree in a bucket of water about I inch from the top of my trees root to trunk union. Leave it in until the soil mix is drenched. Don't water again until the soil is some what dried out. Then post a picture and we can give any guidance necessary. See transplant video of my tree. My tree is larger but the process is the same

Here is a link that might be useful: https://www.youtube.com/watch?v=_AkMFbhlgB0