hi,
in similar situation and posted something myself here the other day.
DS is 2.2yo and often comes into our bed around 5am as its the only way to get him back to sleep again. Although to be fair, he often just wants to get up at this time...which is a whole different story...!
I'm too tired and too pregnant - 34wks - to try to 'train' him to go back to sleep in his cot at that time, so we just bring him in with us. If he does go back to sleep, its invariably ON MY HEAD or diagonally across our super king size bed (who knew a 2yo could take up THAT MUCH SPACE???) so DP and I often don't get back to sleep ourselves, but hang, like you, to the edge of the bed. I feel like a pregnant barnacle....
However, this feels like the easier option, so we're taking it for the moment.
But DC2 due in 6 weeks and will be in a crib by our bed, and I'll be bfing who-knows-how-many times a night, and am just worried that havind DS crawl into bed with us at 5am too, which just make everything worse.
There are lots of threads on here about getting a child from shared bed to cot/bed, so am sure you'll find some hints and advice and some different things to try. One thing I'd suggest - start sooner rather than later. not so much because it might take a long time (it could equally be a lot easier and quicker than you fear) but as you get heavier and more pregnant and more tired, you'll lose the will to crack it - like I have :(
If something is working for you, its not a mistake, but as soon as it stops working, its best to try to tackle it.
good luck