Baby loves breastfeeding

My 6 month old seems to love comfort sucking, he would stay on the breast for hours if I let him. The problem is he is doing it at night now, waking every 2 hours then falling asleep on the breast and just seeming to want to sleep on my breast all night and have it there if he feels like sucking. Not sure if this is a growth spurt or separation anxiety thing, anyone else experience something similar. If I put a pacifier in his mouth he immediately pulls it out!