Miracle Grow makes an awful soil product...and don't be fooled by the "Cactus/Citrus" labeling....
that product is still mostly peat moss, which is not recommended for Citrus container gardening.
You want a mix that is porous, fast-draining, and durable - something that you can thoroughly water and
fertilize, and then allow to dry. This combination will make for much happier citrus indoors during the winter.

John is correct. The small nutrient charge in the Miracle Grow expired long, long ago.
Those nutrients generally last 3 - 6 months at best. So, yes, it is time to begin fertilizing.
However, since this is winter, you'll want to fertilize at a reduced rate - maybe half-strength.
Most plants use nutrients in a 3:1:2 ratio, so it's good to select a fertilizer with the same ratio,
which helps reduce waste and also helps prevent salt accumulation in your soil. I favor a product
by Dyna-Gro called Foliage Pro 9-3-6. Some consider it a bit light on nitrogen for citrus, but the fact
that all the micro-nutrients are included more than makes up for that. Also, I mix Osmocote into my
potting mix, as well as Dolomitic Garden Lime which provides Calcium and Magnesium in the proper ratio.

Move your tree into brighter, more direct light.

Re-pot your tree in late Spring, between growth flushes, into a slightly larger container.
If you find that the tree is root-bound, you'll know that, too, was contributing to its lack of growth.

There'll be lots of help when you're ready to re-pot.

Josh