Firstly gee these tiny tots can be confusing, cant they?!? I remember DD hit an awful phase at about 17 weeks and I just couldnt work out what the heck I was doing wrong! It is a phase and it will get easier. He may be teething, DD started the same things at about 16 weeks also and then never cut a tooth until 10 months I remember reading that during a childs developmental leaps, its like if you were chucked up on mars with everything foreign and terrifying to you and nothing you understood. He is clinging to the only thing he finds safe and comforting. Not much advice sorry, except that it will pass. Hang in there