

I’d really really appreciate any help and possibly reassurance (pls convince me it’s not). Sorry it’s so long.
Based in the UK, and I am a university student however my house isn’t a usual uni house as we’re all mature and pretty tidy. I’ve lived here for four years and have had no rodent problems.
Two days ago while taking bins out in the garden noticed a mouse from one of the bins. I have a really really bad phobia of mice and rats, and then the same day in the evening my housemate saw a mouse move from under the fridge to under the other fridge. We immediately shut the door and went and brought Rentokill fast action mouse killer and kept the kitchen door shut and tried to barricade it so it couldn’t leave through gaps. We have let our landlord know and they will be coming down on Sunday. Since then I’ve been having really bad sleep waking up crying and trying to scratch my whole body because I think there’s rats on me, again a very bad fear of them.
Today I’ve just noticed these weird black things under my bed on the carpet and in some storage bags with clothes. I’ve found about 15 in total after looking for an hour as well as some weird fuzzy on the tissue. The black things are quite small and some had a weird shape not the typical rice grain shape. They’re also really really hard and couldn’t crush them in a tissue but managed to break one in half and it has a dark brown interior. There’s no residue coming off of them either. I don’t think I’ve heard anything while I’ve been asleep/awake at night, and this is the first time I’ve seen it and had cleaned under my bed last weekend.
Basically any advice on if it mice droppings or am I being paranoid. If it is what shall I do going forward, I really can’t tolerate living with them because I’m really struggling and constantly on edge. Also what shall I tell my landlord as well as what shall I recommend them to do, they’re quite confused on things at times as it’s their only property and it was their daughters housing during uni. sorry for the rant, any help would be lifesaving.