As an instructor who has sent over 30 folks solo, I would like to provide my 0.02 cents.
First how long it took you to solo IMO will likely have very little bearing in how good an aviator you turn out to be. Anybody who boasts that he soloed in only X hours is IMO, a pratt as there is much more to flying an aircraft than being able to take off and land under the controlled circumstances of the first solo. I think it is important to understand that the circuit is used to learn how to take off and land. Before you get to the circuit all the esential aircraft handling skills should be there. In my experience when asked to take over students who were not progressing in the circuit I invariably found significant weakness in fundamental aircraft control skills. In all cases I stopped the circuit execises and we went to the practice area to work on the basics. Only when I was satisfied they could consistantly maintain a commanded attitude and airspeed, did we return to the circuit. The important thing IMO is that there is an improvement as you progress through your training and you have a clear understanding of what you are doing well and what is not satisfactory. If you are going around and around the airport and things are not getting better than it is important you sit down with your instructor and have a clear discussion on what he plan is to address your problems. Depending on how that goes a talk to the chief flying instructor maybe in order.