Kellie, sorry you're having dramas with your teeth ATM, it's bad timing that's for sure!

Firstly, it MAY not be dead or dying, it may be able to be saved yet. Your dentsit may be able to put a sedative dressing in the cavity and see if that settles the nerve down. If it does, then he'll put a regular filling in after a month or more.

It the nerve is beyond repair, then yes, your only options are RCT or an extraction. RCT is quite expensive, and if the tooth is already heavily filled, then it may need a crown afterwards as well. It is a good option, because it means you get to retain the tooth, but if you don't have the funds, then there's not much you can do (and I totally understand that!).

If you do end up having the tooth extracted it sounds like your chewing on that side may be compromised, given that you are already missing a tooth. TBH, I hate to see someone your age losing teeth, but sometimes there's no other option. You could have a denture made, but be aware that that's not as easy as it may seem. A denture will be your cheapest option for replacement though. The other options include a bridge, or implants, both of which are quite exy (particularly the implants, although they are by far the best solution).

SO, if you do end up losing the tooth, maybe you could just wait and see how you cope without it. If it doesn't bother you aesthetically, and your chewing is not too badly compromised, then you may be able to do nothing. If either, or both, of those things bother you, then you can look into your options.

HTHs hun, and get off to the dentist quick smart! The sooner you get there, the better chance they have of saving it