Yes! I've felt the guilt, neediness, regret, self-loathing, overly dependent, demanding, etc. I've felt like I was being stabbed in the chest, things could get real bad. Then they got better. At this point, i can email him while he's on vacation if I want to though likely would not. It took years, but now that I relate to him as a separate person, I don't have these issues. The negative feelings come with dependency but they are gone now.

That you question if he's overwhelmed is likely your projection and has little to do with him. If it's too much for him, he can simply not open them, not reply, push them aside till later, etc. Who he is as a person is mixed up with your feelings.

My thoughts are--don't beat yourself up. And remember that your feelings are your expectations of him rather than his own, and he can take care of himself.