This scam has been around for the last few years, but has gained more prevalence in the last year due to the expansion of Bitcoin as a viable currency. You can most likely just ignore it, unless it looked like you had sent the email to yourself. Then it would likely have been a spoofing issue and those can be a little pesky to root out. Just change all your passwords and if you don't already, get yourself a password manager like LastPAss or KeePass. You can also see if your email account has been discovered in any recent data breeches by going to HAVEIBEENPWNED.COM