Hi @Ashleigh36
Really sorry your first few experiences have been negative.
It's a pretty well know fact, the cheaper your listing, the worse and more demanding the guest ( true - I KNOW it makes no sense), so you might want to up your prices.
I would also leave a house manual in a large clear font with plenty of white space in an obvious area and in under a heading housekeeping, explain your cleaning regime and ask that guests contact you if there is a problem with anything. I would also give guests a heads up about the review system - many think that 4 stars is great ( they are more or less told that by airbnb). I'm happy to send you a pdf of my houserules and manual, not saying it's the best thing ever, but might give you some ideas...
I'll also attach a link that shows what some other hosts say to guests in their house manuals re the ranking system.
https://community.withairbnb.com/t5/Hosting/Explaining-5-star-ratings-to-guests/m-p/882631#M217397
what you COULD consider doing , if you are really worried by your stars, is delisting and starting again with a fresh plate ( but with extra strategies in place this time). That will also get rid of your apologetic response to the guest who complained about the grime - (your comment seemed to indicate that there WAS grime and you thought it wasn't so bad. Much better than a defensive aggressive response, but would have been even better to say, that the bathroom is regularly and routinely scrubbed, you are confident that there was no grime and that you were disappointed he didn't communicate with you so you had a chance to clarify with him)
A "New" listing t would also let you take advantage of the special discount welcome offer ( just increase your price 20% so you still get the same amount after the discount is applied) to attract guests again.
Btw - this is just me, but I'd be inclined to get rid of the wash your hands you filthy animal poster in your toilet - some people might not "get" your humour
Good luck! You'll soon find your mojo. It really does get easier. Stay on these boards reading - you learn a lot - both what and what not to do
Cheers