Yeah I've been there OP, many times. Solidarity. Decent pair of wireless headphones and a podcast was all that got me through it. And try and eat before you put them to bed.
I'm currently lying next to a seven year old because sometimes they still want their mum even when they're not babies. I'd rather be that comfort than just leave them to it because it's easier for me. It does get better thought but it's bloody torture while it lasts.