Congratulations Twinthing. Well done on getting to 35 weeks with your twins.
I bf mine until they were 17 months. Stopped because I wanted to get my boobs back.
What you are doing sounds fine. Whilst it may be next to impossible try to rest where you can. I remember the first 3 months being totally full on with feeding. Mums of singletons find it exhausting and so don't be surprised that you do as well. After all, you are bfing 2.
Make sure that the routing isn't just comfort, but is actually for food.
My two were 5.14 and 4.5 when they were born. DT1 (4.5) was and still is a tiny wee thing. She used to fall asleep all the time when feeding. I think that they are just too tiny and get exhausted really quickly. I tried to keep her awake for a semi decent feed. DT2 feed slightly better.
How much help do you have around you? Are they your only babies/children? Take whatever help you can get.
You can also get advice from TAMBA... Twins And Multiple Births Association here They have a helpline 0800 138 0509.
You can always email me on lovelymarslady at aol dot com (losing the spaces and putting in the @ and the .). That can be for encouragement, moaning, advice (such as it is).
You're doing really well. Keep up the good work, but remember to look after yourself where you can.