I surely wish I did. I keep my nails long for that very reason, but of course, that's not really optimal. One thing that I've noticed that is easier to deal with for me is nail scissors instead of nail clippers. Since you are cutting across, it's easier to see that it's an even cut, there's no harsh click, there's not grinding like the emery board. Other than that, I've just had to get frightening good at cutting my nails once and leaving it. (sigh of frustration)

It might help if you do some exercises to help you regulate really well before you start, too. Like, jump on the trampoline for a while. Roll around on your therapy ball. And while you're doing it (or having someone else do it), have your ear buds in your ears, playing relaxing music, or wild music with a good bass to distract you. Maybe have a relaxing weight around your shoulders, if you have something like that. If not, a rice sock is nice and heavy. Sometimes, when I know I have to do something that really bothers me, having that kind of preparation can make it easier.

Hang in there. We all have moments where we get overloaded sometimes. I'm just glad you had your mom there to support you so well. It's not an indication of how bad your SPD is or of how well you control it (except for in that moment). We all get overloaded sometimes. Even Dan. And that you were able to quickly assess it and release that tension is fantastic; it means you gave yourself the tools you needed to let go of that tension quickly. We all seek to do that now and again.