My glands in my neck have been larger for the past month and I had some ulcers on my tongue. I had no other symptoms. Is this allergies?

Time for doctor. I doubt it is just allergies, but to find out you need an exam by a doctor. The ulcers will need a look and maybe a piece taken for a microscopic examination.
Swollen glands. Along with mouth ulcers may suggest a viral process or infection but may be signs of more serious illness like vasculitis. See your doctor.