Soldato
Congrats. Also this ^
Money is no reason to stay. You could be inclined to take a counter offer from your current employer as a bit of an insult, if they value you more highly than they are currently paying you...
I know everyone thinks that employers should throw money at good people as a matter of course but in reality human nature means that if you can get away without doing something you generally will, so I wouldn't always hold it massively against an employer. See what they say when you discuss that you think you're undervalued and go from there. If they don't offer much just move on .