I just had a C Section 6 weeks ago. They did a CT Scan 4 days after it to check for bleeding. All way ok except they found small fluid filled cysts on my liver and spleen
I can understand why you are worried, I'm worried about the problems I'm having as well. Although I can't say how large an enlarged organ is, I can say that I also had a CT about 1.5 months ago and a fatty mass was found on one of my adrenal glands. Like you, I'm worried about it, but was also told to come back in three months to have it looked at. Just as you, all of my labs came back fine. I think that if the doctors were seriously concerned about the enlargement, they would have set something up right away.
If it makes you feel better, you have more than the right to get a second opinion, and I would suggest getting one. It may clear your mind a bit.