Hard spot on breast - mastitis?

Today I developed a hard lump on my breast. I have been breastfeeding on demand for two months now (my LO is two months old) and haven’t had problems until now. It is the shape and length of a finger and is a hard lumps but has some small lumps on it too. Is it mastitis? Have you had it and what did you do? I don’t want to take antibiotics (I don’t even have a PCP at the moment). What did you do to make yours go away? I did a warm compress and that felt nice but it’s still there. Baby fed for ten minutes but it’s still there.

Side note: my hubby and I had sex this morning and he gently sucked on and licked my nipples. Could this cause mastitis?