Bed-sharing safely?

My three month old son will only sleep quality sleep with me. And I really love having him next to me. I'm a single mom so I have the bed to myself and I only have cats but they want nothing to do with him at night. I have nothing on my bed except a blanket at the very end so I can cover my feet and just a pillow for me. I just worry about him snuggling so close to me that he'll suffocate. I'm always alert so obviously I'm never in a deep sleep and I try to keep a hand on him.

I just wanna know if there are any mommas out there with other ideas on how to share my bed as safely as possible.

Also, what's a good sleeping position? I always sleep on my side with my legs bent and my arm underneath my body stretched out above baby's head. But this position kills my hip and is uncomfortable.

Please no comments on how I shouldn't bed-share. I've chosen this for my son and I because it is the only way he gets quality sleep.