It seems a bit strange that your therapist immediately responded to your email of quitting and told the front office on a Sunday.

Hope if you really want to continue therapy I would suggest emailing your therapist back and telling him you changed your mind. It also might be helpful to just stop the emailing until you have a chance to talk to your therapist in person it seems to be causing you more distress and not helping anything.

I know you said your first pdoc told you you could keep in touch because you remember he did not have good boundaries and that entire situation did not end well. As stopdog said it's fine to ask your therapist that question but you must remember that any therapist that holds good ethical boundaries it's almost always going to say no. In addition due to ethics and boundaries I'm sure no one would say yes in writing on an email. If you really feel the need to ask those types of questions it's probably best to ask that in person but again he prepared for an answer that you probably don't want. Therapist are paid professionals and not meant to be friends outside of the therapeutic relationship. This is not a rejection of you it is just the ethics they are bound to uphold.