my former employer is calling me back with double the salary

I’m really in a ridiculous situation right now, the company that fired me three months ago is calling me today to come back. Moreover, they’ve officially offered me twice what I’m currently earning, but they really upset me when I left. I’m happy with my current job, but the money situation is very tempting. I honestly don’t know if I should be proud or act sensibly, I’m quite undecided.