Should I get my bunny another companion?

I think it sounds like your bunny is very happy with you and you are very happy with it. I would not recommend getting another rabbit because it would just upset the balance. If you are comfortable with having only one rabbit, you should only have one rabbit and as long as you spend time with the rabbit you do have, I don't think she will get too lonely. The biggest problem with getting a second rabbit is that rabbits (like most other animals) are highly territorial. If you were to bring in another rabbit, I can guarantee you the two rabbits would fight. They might just fight for a day or two and get over it (although rabbits can do a lot of damage to each other in a day or two) or they may continue to fight for the rest of your lives. Adult rabbits that weren't raised together are particularly inclined to fight, so that if there was fighting even between the sister rabbits you had, there will definitely be fighting between two rabbits that weren't raised together. I think you've got a good thing going with your rabbit and it sounds like you're a very good bunny parent. Don't stress yourself or your bunny out by bringing another rabbit into your apartment.