It's taken me days to reply because guess what - I have an 8 week old baby and a 21 month old toddler. I found the first 6 weeks or so the hardest and then the night feeds started stretching out and it has got a bit easier sleep wise but it's full on with a tantrum throwing toddler. I hope you're getting some more sleep! Try to get your DH to take your toddler out on the weekends so you can catch up on some sleep and maybe someone could take her midweek for an hour or two. If you can top up every now and then it makes a difference.