I definitely think you should talk to your therapist about this ASAP. Therapists really do have a dangerous job, and this is the sort of behavior that is a red flag for them. If you deal with it early, and find a way to deal with the attachment pains (and oh, I understand those!), you'll definitely feel better, and your T probably will, too.

I talked to my T about sometimes sitting in his empty office parking lot at night when things were bad at home, and that one time I felt like taking a picture of his office window, because he leaves the lamp on at night and it felt safe. He gave me permission (I'm a photographer), and in return, I gave him a nice varnished black and white print of his office window through my rainy windshield one night. If I hadn't asked first, I would have felt awfully stalkery about doing that.

I certainly don't think you're a bad person, nor done anything bad, really. It is the kind of behavior that can become a kind of toxic secret in therapy, and lead to a shame spiral that can cause all sorts of problems. Good on you for tackling it head on!