I would go further and say you did NOTHING wrong. You had a concern, went to get more information on it, and made a decision about how to proceed. That's exactly what you need to do as a parent.
Personally, based on what you describe, I think it's possible that everything was just fine. Some babies are really efficient at nursing, and can get the breastmilk nutrition they need from as few as 5 nursing sessions per day. But I agree with the previous posters that at this age, it's best to err on the side of caution and back off on the solids if it seems to be interfering with nursing, since that's the priority right now.