SPIDER MITES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

like Steve says, its spider mites that are probably causing your issues. Look for the tell tale veil like webs at the joints where the leaves meet the branches (could be whats holding up that leaf stem). If you have a magnifying glass handy, you can also see the mites on the leaves especially on the underside of the leaves. You can find lots of info on treating them on the forum or google.

I don't know anything about that brand of fertilizer but I would not exceed the recommended amount and frequency noted on the bottle. You may also want to hold back a bit with the fertilizer since the tree is in a weakened state. Fertilizing a weak tree sounds like it would help but can actually cause other problems.

You may also want to consider switching your soil mix to either the "gritty mix" or the "5:1:1 mix" both of which are almost perfect for potted citrus trees. You can look them up on the forum. There are no good per-mixed potting soils for citrus, even ones that put "for citrus" on the package will still compact too fast and cause root rot before you know it.

I know it sounds rough but you may also want to consider removing the fruit since your tree is still very small and very stressed, this will allow it to focus on growing more.

Oh great thanks for the tips!!!