Needs a lot more light. Take it outside in shade first for a week then in half sun for a week then full sun for the rest of the warm weather. Meyers need more sun than any other citrus. Get a Meiwa or Fukushu kumquat tree next.

I wouldn't worry too much about the bugs in the soil, but it may indicate the soil is staying too moist.

A good spray of water on the leaves can be a first step at dealing with pests. If it is spider mites, you want air circulation and frequent misting.I take a damp paper towel and wipe the top and bottom of a few leaves - if it is smeared with red or yellow, you have mites. Later you will see the webs and speckles.

Do try to slowly get it outside.

I agree with Steve, look into kumquats when you are ready to expand ;)