What is this behavior?

Steph&Harry08

DS is almost 18 months and just since the past couple of days he is being acting weird when nursing. He only latches very shallowly and does a quick suck--which feels very uncomfortable for me--he's not really nursing, it's like he is playing and when I tell him to either eat or I'll take it away he starts crying, he latches back on and starts actively nursing for like a few seconds than he's back to playing, so I just stop which causes a melt down. And at night (we bed share and he nurses about two or three times) he's bitten me a couple times. Any thoughts? TIA!