I understand your hesitancy to report this person to the police. If he is connected to the first attacker, then it would make you reluctant to report it. You may still want to consider it, however. Maybe talk to your therapist about it and see what she thinks.
This incident may be a set back, but not for long. You already have the tools to get yourself out of the hole and now you just need to use them again. It may be that you fell a little backwards, but giving in will only make the attacker win and you will suffer for it. You already have power over what happened because you seek help and push to get better. You have not given in, and that makes you stronger than the attacker could ever be.
I know you feel this is overwhelming. That is ok to feel. It just occurred so it will take time for you to feel better. Allow yourself time to adjust to this new situation. You are probably still in shock and your mind and emotions need time to get used to what occurred. Once you allow the initial shock to pass, you will be able to face this and work through it.
Try not to keep this a secret. Certainly do keep it from people you do not trust, that makes sense. But from the people that do care, don't feel you are burdening them with your problems. Friends and family that are truly there for you will not mind. They may welcome a chance to help you through if you let them try.
I am here anytime you need to talk,