What do I say about why I left my last job? - first time posting

I have an interview next week and I am unsure how to explain why I left my last job as a web developer. It has been a long 4 weeks. I also do not want to seem like a risk. Do you mention numbers?

If a company has been in the news for layoffs, you can mention that. Often the interviewer already knows.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.