I am a foster parent and I have an 8 months old and a 3 month old and I am expecting one of my own. We don't take kids over 1 because they are a lot of work. I do find it draining and I have DH to help.
It's hard to say how you will feel. We are not used to the toddler age so we find it work, you have already been dealing with that age so you have gotten used to it. I would say that make sure you are organized and have things to keep the kids busy. In Canada we have a place run by the government where we can take the kids and they can play and do activities, it's free. These are great because although you have to be there, it keeps the kids busy, the mess is outside of the house, and gives you a little bit of a break.
People think we are crazy for having 2 under 1 but it's really all what you get used to. I am sure you will find your way and get through the tougher younger days.