Hi, I have a 19 week old who is doing the exact same thing & it is driving me crazy. I feel like I can't get anything done while shes awake, because all she does is whinge & I have to keep going to her & then she's all smiles. She also use to be very content to play on her own. I get these weekly updates on babies development & it says -" Your baby knows she's the star of the show, and like all great divas, she'll want your eyes on her at all times. She thrives on your attention. Don't be surprised if she deliberately tries to get it by dropping things, banging objects, or even crying out when you turn away. She's not acting up, just discovering the principles of cause and effect — when she calls, you jump!" So I'm hoping it's just a developmental process she is going through & it will pass soon. I also remember my youngest son doing it. My little girl has had her hands in her mouth for past couple of months & I don't believe she is teething, babies just enjoy sucking on their hands. Hope that's all helpful & good luck to both of us.
Cheryl, Qld, 2 boys & a baby princess