I feel for you man. Your experience in TKD is emotionally getting in your way. Someday soon it will make your aikido technique that much better. I've seen this with so many people who start cross training and I've experienced it a bit myself. Most people give up because they don't like the feeling of "being a beginner" again after attaining years and rank. At least, you are getting your frustration out of the way at the beginning of your aikido career. It is all up hill from here.
People can correct me if I'm wrong (and I'm sure they will), but I think that the one decade in martial art hump that you and I are at is a common place for frustration no matter what one is learning. Just like in my doctorate, I just got to the point where I was proud of what I've learned so far. With that comes the knowledge of how much more is out there.
Hopefully, we will train together someday and when we do, I hope that we are both enthusiastic beginners again.