Dear Jue H, perhaps I am no expert in BW since my dd also has "periods of riot". Once in a while she starts waking early from her naps for a couple of days or in the middle of the night but i try to sh/pat her and just go through this period. To be honest, the third month was the most difficult for me in terms of keeping up with EASY but once we settled our 4 h routine it got better with each day. Just be consistent and eventually it will work out fine!
just a couple of suggestions - have you changed anything in your routine that could have caused change? new people in the house (MIL visiting:)?) new toys, activities?
has he been waking up in the night as well?
has he slept well during the day before?
in her "BW solves your problems" book Tracy mentions that the third month is the time when any inconsistency in baby's sleeping habits comes out. But it is all manageable!!! just try calming your baby down. At that age it happened quite often that my dd would wake up 30-40 minutes after going to sleep and i'd pat/sh her for the next 1,5 hours. super exhausting. to go through the tough times we had, i wrote "translation from babylanguage: crying hard - please help me learn to cope with it", printed out and hung by the DD crib. helped me to keep the perspective
I am not sure whether i did everything right. But by the forth month it all worked out fine and now she sleep very well with only very rare an minor surprises.
you could also post your routine here so we could come up with more suggestions
please do not worry about his making a fuss becoming a habit. I am pretty sure he does not exactly enjoy it as well!
Hugs for you and all my support in this hard time