Sounds like sleep regression. My baby is just like that previously and he will only sleep on me. I babywear him so that he can sleep on me while i do my housework. I used to follow the websites but then i realised that every baby is different so long they are healthy and active, its okay. It will pass real soon. Hang in there mummy! Dont worry too much, you are doing just fine!
try using carrier to make your baby sleep or yaolan. sometimes baby don't feel secure that's why they can't sleep properly. and make sure you set like a routine for your baby soon.
My 4 mths + also get 2-3 nap of 20-30mins only. He also sleep very little in the day since NB. He is growing quite well despite all that ... currently at 9kg ..
sounds like sleep regression..don't worry..this too shall pass!
https://sg.theasianparent.com/4-month-sleep-regression