Congratulations!
Here is my input. My son was 36 mths when I became pregnant. He nursed throughtout the pregnancy and is still nursing!
He was old enough to explain that when my milk supply decreased around 7 mths that lots of really sweet milk would come with the baby. I think it turned around 8 mths. I did take some herbs (blessed thistle) to help with supply.
I didn't get 'touched out' but there were times, usually late at night where I would feel like I would fly thru the roof if my son didn't let go of the nipple, so I would just nurse as long as I could mentally handle it and then gently tell him that mommy needed a hug and cuddle. Worked for us!
Both of my boys are happily tandeming now, although my soon to be 9 mth old likes to push his brother off of "his" side as they affectionately call them. LOL
My poor dh says now there are no sides left for him!

HTH and best of luck!