Clingy Baby?

My 6 mth old boy has just stsarted to become very clingy and demanding of my, or anyones time. He want to be held all the time or for you to sit right next to him or else he is screaming as loud as possible, straight away. This makes it really hard for me to spend time with my elder daughter, as even if we are in the same room but in his mind to far away it starts. I do include him sometimes but she deserves time with just me as well. It is driving me crazy I can't get anything done and i sick of people saying i spoil him, when i don't, it only started really about 2 weeks ago and i have already had enough. Any suggestions.