Thank you for the question.
I'm sorry to hear about the concerns you have after your procedure.
You should be aware that a significant percentage of patients at your stage of recovery will feel that they are "too small".
I have found, that with time, as breast implants “settle” (drop and fluff) that the resulting breast size/shape seem larger. You may be able to see this for yourself if you stand in front of a full-length mirror and “pull up on the breast skin and down on the breast implant"; as the breast implant moves into the lower part of the pocket and the nipple/areola move up, the breast may appear to be larger in appearance.
I would suggest you wait at least 3 to 6 additional months before you make any decisions regarding the results of your breast augmentation surgery. This waiting time will allow you to (potentially) physically and psychologically adapt to the new body image.
If at that point, you are convinced that the breast implants are too small ( assuming the breast implant pockets are otherwise doing well), revisionary surgery is a relatively painless procedure.
In the meantime, continue to follow-up with your plastic surgeon to discuss your questions and concerns.