From the subline to the ridiculous!

OK for a couple of weeks Seth has been grouchy, eating little (5oz max) and often and not sleeping at all at night time (4 hr max) then only 20mins here and there in the day, well last couple of days he's been taking 8oz every 4 hours and last night we got 8 hours out of him, we're also getting one to two hours naps in the day morning and afternoon. Whats going on!? Do you think this is a growth spurt and he'll revert back to his horrid ways or do you think now he's nearly hit 12 weeks he's finally settling down!!
Please tell me its the latter!
S & S xx
11+4