Wisdom tooth LARGE cavity. SEVERE pain similar to when my other wisdom tooth hurt, which was pushing on a damaged nerve before extraction. 2nd molar was removed years ago to give current wisdom tooth room to grow. Dentist appt next week. EXTRACTION??

Speak with DDS. Let the dentist evaluate the tooth prior to extraction/implant. Was the third molar orthodontically moved into the second molar space to avoid open contacts? There are many variables, which need the dentist's expertise for long term success.
Severe pain. Your severe pain is an indication of an infection. Don't wait. Call your dentist and move up your appointment. Since you have a large cavity your tooth will be evaluated as to what the best treatment would be, possible root canal or extraction. Get this treated asap.
Possibly. Can't understand why the 2nd molar wasn't restored and the wisdom tooth extracted years ago. You're probably looking at root canal therapy and a crown. At this point it may be better to extract the wisdom tooth and place an implant in that second molar site.
Emergency. First, if you are truly in severe pain & can't get a dental appointment until next week, see if your dentist can get you in sooner. If it were me and he/she couldn't I certainly would find another dentist, at least for this emergency. Large cavity? when was your last dental visit? perhaps you need to go more often. What is best treatment requires exam and x-rays which we can't do over the internet.