It's hard to answer because you've given a conflicting description of what's going on. You say you avoid eating on a particular place, but then you also say you have pain upper and lower which would indicate the pain is all over the place. As someone with really bad teeth and therefore a lot of dental work, I can say that at least in the US most dentists have emergency appointments, and if you can't get that with your dentist there are other dentists who do that. I find that here, younger dentists are available, but older dentists only work a few days a week and are often unavailable. I suspect that you have a problem in a tooth or an area of your gums and it feels like it hurts all over because it is affecting a nerve and that can cause pain to radiate, making it hard to know where exactly the pain is coming from. This is especially true with cracked teeth. If the pain is horrible, that usually indicates a filling has expanded and taken out the nerve, causing the nerve to die. The usual way to fix this is to get a root canal from an endodontist or get the tooth pulled. This kind of thing doesn't show up on an x-ray, even a digital one, and cracked teeth don't either. A dead nerve is determined by a heat test -- if the tooth is very sensitive to heat, the nerve is dead in that tooth, and if it hurts to cold, the nerve is alive but stressed. A CT scan can show bone loss, which can indicate a cracked tooth. Most dentists can't actually do this diagnosis all that well, though many younger dentists do try to do everything whereas older dentists would send you to an endodontist or periodontist if it isn't a cavity. If you can pin down the tooth that is the problem, you can get temporary relief from clove oil, and I mean real essential oil, not just something that smells like a clove. This will only work for a time and then it stops working. When you have pain and a dentist tells you there's nothing he can do because it doesn't show on an X-ray, you might want to get a referral to an endodontist who has a CT scan and who is better at diagnosis than general dentists. It can save a tooth, because sometimes an old root canal has gone bad and it can be redone but if your dentist keeps telling you it's nothing, as one of mind did, it can be too late to save the tooth. So be assertive, it's your mouth and you know best how much it's hurting. Now, it could be lots of other things. If you do clench your teeth, that can lead to a lot of sensitivity over time. If you do that, most dentists will make you a mouthpiece that cushions that. So do see your dentist, but if he can't make the diagnosis, get referred to someone who can. One other thing that helps some is a homeopathic remedy called hypericum perforatum. It's basically diluted St. John's Wort, and for some, it really helps with nerve pain. Others find relief from chamomilla or magnesium phosphate, two other homeopathic remedies. Again, these work for some and not for others. Hope it gets resolved quickly.
I am sorry to hear of your pain, I know how wearing it can be.
The answer is helpful and covers a lot of things.
Is the pain all over your mouth, top and bottom, left and right? If so, it sounds odd and is maybe referred pain from one point where there is an issue. I would have thought it is highly unlikely you would get pain all over like that though.
Could the pain be in your gums? I am wondering if it could be a gum infection if it is all over.
I did manage to get to see a dentist in the UK. They put you on a waiting list which is not so much a waiting list as a triage list. The dentists, in my area at least, go through the list and triage patients into emergencies and urgent. Due to Covid, many have only been seeing emergencies. Hopefully, you will get triaged as an emergency or urgent. If your pain is all over your mouth and possibly a gum infection, then tell them it is all over.
If the dentist does not make an appointment for you soon, then it may be best to ask to see your doctor. A gum infection can be treated with antibiotics and although a doctor will not be happy to deal with a gum infection, if they know you cannot get a dental appointment, they will have to consider that and not ignore you.
Good luck and I hope you get some help soon!
Glad to hear you have an appointment with your dentist now and that the painkillers are helping. I hope you get a solution soon.
Just to add that while you are waiting for your appointment, you can alternate Ibuprofen with Paracetemol (Tylenol if you are in the US). Usually, you can only take either medication on 4 occasions per 24 hours, but the painkilling effects tend to start to wear off after about 3 hours. For example, if you have taken Ibuprofen and its effects are wearing off before you can take the next dose 4 hours later, then you can take Paracetemol to maintain the painkilling effect. This can help to cover the periods when the painkiller you are taking is wearing off and before you can take it again.
Please be careful though to alternate these medications as both can be toxic if taken in higher-than-recommended dosages.