Sometimes, especially if a person has hardened stool that is not breaking down during the colonic, a piece of stool can clog the tube preventing a thorough release. Since you mentioned that you were leaking, it is my guess that this is what happened and she had you use the toilet to eliminate the blockage. She may have had to unblock the tubing while you were in the bathroom, as well. And using the toilet after the colonic is very common. Since this was your first colonic it is unlikely that the procedure would have cleared your entire colon and virtually everyone has to expel additional stool or, at least, water.
Also, some colon hydrotherapists will offer a discount on a series of colonics...but to take advantage of the reduced rate, they will ask to be paid upfront. Actually, she gave you a very reduced rate for 3 colonics...$150 vs. $210. Most hydrotherapists that I know of will only reduce their standard rate by $5 or $10 per colonic for a series.
Nevertheless, it is clear that you are not comfortable having a female perform this procedure and that alone will inhibit good results. In order to have a successful colonic, you have to be able to relax. If you want to try another colonic, I would suggest that you find a male colon hydrotherapist. Otherwise, you can perform multiple enemas yourself.
Also, make sure that you are drinking sufficient water. Hard stool is almost always due to dehydration.