Is Ruby Pregnant or Mastitis?

Hi, We adopted a retired milking goat named Ruby. She is about 7 years old. I was told she had her shots, and she has been very healthy and happy since we got her about 6 weeks ago.
Last few days she has had one Teat?(not sure of spelling) swollen larger than the other. She is not being milked, and hasn't for a couple years, I think? They were both the same small size before.
She is laying down in the Sun more, and I noticed she rolls to the side to lay.
As a mother of four myself, this looks like she may be pregnant?
I am worried she may have mastitis? but don't want to give her antibiotics if it's not necessary.
Ruby is a big Girl!! but she is round bellied, can't tell if it's baby related?
I would appreciate your help.
I uploaded photos, not sure if it worked?