I killed it!

Last year I bought my very first plant with my former roomie who is a horticulture major. From the beginning I struggled to keep it alive. The first day I brought it home it shed all of it's leaves and I thought it was dead. It finally came back and was looking great. Now it looks like this and I don't know why...maybe it is because my horticulture roomie moved out and now it is neglected. I tried but I definitely don't have a green thumb. I guess I'll stick to silk plants for now. :(