Hi , I Am 38 And I Found A Lump

Hi , I am 38 and I found a lump in my neck .I went to the Drs. Today a walk in clinic , he felt it and found a couple others . He said they are swollen glands , he got very quit and ordered blood test and x ray . I'm super scared , he put me on a antibiotic and told me to take 3x a day . I'm worried ! Please help explain why theses would be swollen other than a cancer .
Thank you !