Lump in the back of my neck and pain?

I've had a headache for an entire week now. It hasn't gotten much worse and it hasn't gotten better. I've also been extremely tired and sleeping a lot this week. I just attributed it to my period, but I woke up this morning and I had a lump on the back of my neck. I do have a piercing on the back of my neck which has been red and sore for a few days and the lump, which is about the size of a small grape, is a few inches below it. The lump is sore to touch. Also, I started developing a lot of stiffness in my neck. I also have chills and hot flashes, and my lymph nodes are swollen. I'm seeing a doctor tomorrow, but what could be wrong?