Most men will experience erectile issues at least once in their lives, if not more, and stress is a big trigger for that.
It's easy for us to say to not worry about it and that it will work itself out, but I'm sure it's not that easy for you to just do.
Has your stress ended?
What you can do is focus on connecting with your wife in ways that aren't about your erection. Touch her, hug her, kiss her. Focus on foreplay, her orgasm, and not about penetration. Do that for a little while, and just relax about sex.
If she wants to use her hands or mouth on you, do that, but there are lots of other ways to be intimate and orgasm without penetration.
Since penetration is causing you stress, just don't focus on that for a week or two. See how that goes.
If stress and/or anxiety continue, don't hesitate to see a therapist to help. This is totally normal, and it happens to everyone.
If the erection issues continue, see your doctor to rule out any physical problems.