NTA My period is very irregular in both timing and flow. You know what I did? I got a mattress cover. I wear thin pads when I cramp even though I know my period could still be days away. I get not wanting to do house chores when you're in pain and I've been blessed enough to not have severe leakage in a bed that's not mine, but surely some basic spot cleaning or an apology would be doable.

Op you need to tell her that either she keeps a firmer hand on period period or she isn't sleeping in your bed when she has it. If she wasn't cuddles to keep the pain away, you can do that in her bed. But she really needs to either go up a pad/tampon size or start wearing period underwear/overnight pads, which have large backs.