Does this sound like a developmental leap?

My baby is 4 months old this week (16-17 weeks), he had slept through the night (8pm-6am) since he was 6 weeks old (doctors was okay with it, his a healthy weight and eats good), easily self soothed to sleep for nights and naps, was always happy and smiley, when he slept there was no noise that could wake him, he slept through anything including 2 kids running around like crazy. Such an easy baby, on the evenings when dad's home I could just put baby to sleep and go to the gym, I had no worries.

Now the passed few days my baby's been acting different, his having fewer naps, really short too, when he gets tired he now screams and cries, only thing that calms him is being on my chest and he drifts away as I rock him, I cannot put him down at all, if I do he wakes and cries. Daddy had him last night so I could shower, half way through I hear baby screaming non stop, I could tell dad was struggling to calm him because it wasnt getting any better, so I had to get out and take him, 2 seconds in my arms his smiley and falls to sleep on my chest. His not sleeping through the night anymore either, his having 3 bottles on the nights now but his not awake either so we go back up to bed straught after a feed.

Also his easily startled now too, when his asleep on my chest, if his older brother just drops one toy, baby jumps hard enough thag sometimes he headbuts me, goes back to sleep after too.

Also his head is hot to touch but no high temperature or fever.

This is all so strange of him.

His also been on an antibiotic steroid cream for the passed week too for a terrible eczema, it's worked amazingly and today's the last day on it, have doctors for it tomorrow, could that also have something to do with it or is it a leap?

I'm not completely worried or struggling, I don't mind the extra loves and cuddles and I could do with a break from the gym if he only wants me with him, I'm just curious if this is normal to change so much so fast? My first was always like this from birth and was a difficult baby so I'm not sure if it's normal to go from being such an easy calm baby to this.