4 month sleep regression a real thing?

I have a 4 and a half month old baby. Hes been sleeping over night really well for the last month or so (9pm to 2am to 8am are his usual wake up times). 2 days ago he suddenly started sleeping a lot worse, waking up every hour or 2 during the night and only taking half hour naps during the day.I had previously seen that babies go through some sleep regression around 4months but I'm not sure if this is a true thing or just something people say? A quick google search says that it does happen but I wanted to hear from some real people about it. Could he just be teething? At his 4 month check up the pediatrician said he felt little bumps where his teeth are growing. via /r/Parenting https://ift.tt/2wAmn9P