Teething signs in a 5 month old

My son turns 5 months next week and I am interested what were your littles first sign of teething and how long it took for the tooth to poke through? My son has been more fussy and irritable for no reason, eating more, and not taking long naps at all! He’s also been putting everything in his mouth. Our ped said all that is normal behavior for a 5 month old, but my son is never ever this fussy!! I know teething can happen over night so I just keep looking at his gums when I have the chance. If this is teething we are going through, what did you do to help your baby?