I realise it is dangerous for me to be sleeping with her held in my bed.
When you say held, do you mean you are both lying on the bed, with your arm around her? If so, this is perfectly safe for a breastfeeding mother like you, provided you are following the Safe Sleep Seven (on Lullaby Trust website) - no pillows or duvets near her, sober etc.
(If you mean sitting up with you holding her than yes, there's a risk of her falling out of your arms, best to create safe space on the bed and lie down together)
Breastfeeding, even if not excusively, produces hormones which put you in a special state of alertness even whilst sleeping, and keeps your baby in a lighter sleep - this keeps your baby safe - safer than in a cot where they can sleep too deeply. It's why SIDs does not exist in countries where bedsharing is the norm.
https://www.basisonline.org.uk/hcp-bed-sharing-and-non-breastfeeders/
Bedsharing can also help with reflux, as baby can fall asleep feeding in the side lying position which can help keep milk down. Some mums do the classic 'cuddle curl' position when bedsharing, but wtih baby's head elevated slightly by resting it on your arm, to help with reflux.
Possetting is totally normal though - they say it is simply a laundry problme rather than anything wrong with baby.
Are you seeking support to to increase the amount of breastfeeding or you're happy with your current set up?