Might be a leap, we’re just going through it too with our 5month old. It lasts around a week usually.. which feels like a long time!
Could be a growth spurt or teething
Yes, baby was sleeping great. No 4 month regression but only got up once in the night now it’s 2-4 times.
My baby has been waking up extra in the night the last few nights and just today I noticed a tooth pop up.