I have a Meiwa Kumquat tree that I'm growing on my windowsill. I bought the tree (it's grafted) when it was 2+ years old and had 10+ kumquats on the tree. As it got closer to winter they ripened and were delicious. As winter has progressed my tree has had it's leaves lose their luster, go pale and get some brown spotting.

The leaves on the lower end of the tree look healthy but a lot of the upper leaves have had this issue. Just last week I gave it a bit of fertilizer but that hasn't helped. I water it 2-3 times a week and it spends most of it's time outside in front of my window, getting plenty of sunlight.

Please see some pictures of my tree and some of the fallen leaves here: http://imgur.com/a/GAO7S

Any ideas on what is happening to my tree would be extremely helpful, I'm a bit lost!