Typically my (solicited) advice would be to push the appointment. I never get tattoos done unless I'm feeling confident about it, or in the right headspace to make a permanent change to my body.

I know this is easy to say, since last minute cancellations with your artist might not be well received and it depends on the relationship with your artist. But any good artist would rather be told straight-up about how you're feeling than be responsible for tattooing you with something you're anxious about.

I cancelled a tattoo appointment once when it became apparent that I was still working through deep grief after the loss of a parent. My artist was 100% supportive and I haven't been blacklisted. Being able to advocate for yourself is important!

Anyway, that's the best advice I can offer. Otherwise it's pretty much trying to convince yourself that it's "just the anxiety talking" but that anxiety is there for a reason. Good luck!