Hello - If I were you, I would insist upon seeing a throat specialist. I know a person who had similar symptoms for several years. Now he has learned that he has a cancerous tumor on his tonsils and is having radiation to treat this.
That is not to say that your problem has anything to do with that, but the fact that you have lost weight, get night sweats, feel tired, and have swollen lymph nodes seems to indicate that your body is trying to fight something and is trying to tell you that!
These days, we almost have to be our own diagnosticians. If you learn that it is nothing, then that would ease your mind and stop your worrying for no reason.
But, if it turns out to be something serious, you will be able to start treatment.
You should write down all your symptoms and take a copy of your MRI report to your next appointment and not let the doctor leave you until all your questions are answered to your satisfaction. Good luck!