Whenever I have used my safeword I had ended up feeling like that. Challenging myself as to whether I had actually just wimped out. It is very hard to say, and it is right that now, after the event you do discuss it with your dom. You both need to learn from the experience. But remember, at the point at which you used it, you felt as if you had been 'pushed over the edge' and you could not take any more then. Hind sight is a wonderful thing, which we do not have.

Don't be too harsh on yourself, you are in the process of discovering how far you can take your submission. There are no right answers to that question, other than what is right for you; but as far as your dom wants to take you is the wrong answer!

You are right you should not fall into the habit of using your safeword as an easy option, but when I was struggling with just this issue, I was told that if play never took me up to the point of me having to use my safeword it had never filled all my submissive space.

Hope that helps a little

cariad