You have an eight week old baby that wakes you up every two hours to eat. You are not sleeping well because the baby wakes you up, which is totally normal. I think the only cure for that is to do your best to get through it and know that eventually, baby will start sleeping for longer stretches at night. Nap during the day when your baby naps. That was the best way that I found to help with the tiredness during the day.
I don't think there's any supplement that can help you with this situation, you just have to bear through it. Par for the course when you have a young baby.