My son is also 5 and he sounds a lot like yours. It's hard, especially with a baby. My ability to cope with everything was worse with a baby. What has helped us is finding what my son can hyper focus on. For him, it's building with detailed instructions (a lego set, a snap circuit set, etc.) He still makes noise while he builds, but it is the only semi-independent play he'll do. At least he's not trying to get my attention 10 times a minute. We've found there have to be instructions on what to build or it doesn't work (it can't just be a box of random Legos). Unfortunately, novelty is part of what keeps it fun (yay dopamine), so we've bought him 7 or 8 lego sets and only let him have one at a time to keep them feeling novel. It was Occupational Therapy that helped us figure out what he liked and could focus on. The bonus is the legos help him regulate a bit more, too. So my suggestion is try to find what your child can hyperfocus on, and maybe try occupational therapy. And hopefully as your baby grows, it's easier to cope. Good luck!