Well, if it's anything like the iD/iD L, your character probably is completely hungry or the happiness bar is way down. Have you checked your Tamagotchi's stats? Maybe try feeding or playing games and see if those flashing hearts disappear? I'd try that before resetting and downloading.
Did you recently feed him something different... maybe honey, or something that could be a love potion? If it was a love potion, the effects should have worn off after about 15 - 30 minutes. (Sorry, I don't remember how exactly long the effects normally last, but it's in that range.)