Hole in back tooth - feeling down

[Cheeseandolivesplease]

I'm 45 and I do my best to look after my teeth - I have a private dental plan which I pay monthly for, and I ensure I attend my check-ups every 6 months. The last time I saw my dentist (Jan) all was fine apart from a tiny filling required on a very back tooth.
However, the past few days one of upper back teeth has started to niggle a tiny bit. I've been flossing tonight and a big hole has presented itself at the back of the tooth. It is now starting to hurt. Feels deep.
I am going to try to get seen tomorrow as it is throbbing and food will get stuck in it.
But I'm so fed up. I haven't got the money for a load of work.
Also, should this not have been picked up at my last appt in January? I'm not dentist, but wouldn't there have been initial signs of decay?

I don’t know if the dentist would have seen it at your last appointment, but if you have a dental plan where you pay monthly, would the repair to this tooth be covered already?You’re saying you haven’t for the money for a load of dental work, but surely that is what the plan is for?

@Katherineryan1986
Unfortunately not. I pay £20 pm for 6 monthly check ups/XRays and that's pretty much it. A simple filling cost around £50, my root canal treatment and crown a few years' back around £800 in total.

Did you have an x ray in January? If yes it can’t be that bad already. Hopefully it’ll just need a filling - good luck

@StormGazing Yes - a number of Xrays. It looks really deep and is quite painful. I think that's what has surprised me as it's not like I haven't been attending regular check-ups?
Begs the question what am I paying my money for?

Does your plan not cover treatment? Presumably you are due a check up about now anyway.

@LIZS No. It will only cover the check-up cost which is due around now 😞

A hole or a chip? I’ve damaged teeth eating a salad and biting down on an indestructible seed, and biting on a stone cunningly masquerading as a chickpea in a stew.
There is so much to go wrong with your teeth, which is why there are no guarantees with dentistry and the government want it out of the NHS.

Thanks all. I got an emergency appt as it was really hurting.
Deep filling, cost £200. Money I haven't got!
Dentist said it is very near the nerve and the filling may not sort it. If not, referral for root canal which is going to be around £1K. I definitely haven't got that - that's almost as much as my monthly rent.
Fed up 😢