Like MotherofToddler says, it's an EXTREMELY tough age. My two are 8 and 9 now, but I still remember. It gets SO MUCH BETTER as they get older
As far as having a second... mine are 19 months apart and it's been brilliant. The whole "two in diapers" phase was survivable and now I'm reaping the benefits of all early hard work: they play together, keep each other company, help each other, challenge each other, etc etc. I wouldn't have wanted them any further apart in age.
Hang in there... it'll get better
