Caroline

Yeah, Dr. Google is pretty scary. I second the advice to go to an ENT (ear,nose throat) doctor which is a nickname for their formal title: Otolaryngologist
The ENT may take a biopsy right there in the office. Only a biopsy and pathology report confirm cancer. But ENTs also see lots of non cancer sores and recognize them so it may not even be necessary.
You can also ask the ENT for a CT scan of your head and neck.
At this point, telling you to RELAX is not going to help although you do need to take a Deep Breath and CALM DOWN.
As for words of encouragement, if one your lymph nodes on your neck has not expanded to the size of a golf ball, that's a good sign. Also none of your symptoms mean it has to be cancer, each and every one of them, and even all of them together can have other non-life threatening causes.
But your peace of mind requires you to see an ENT in my opinion.
Charm