My son is 14 months old and I’m still breastfeeding. Never had any problems before but today my left…

My son is 14 months old and I’m still breastfeeding. Never had any problems before but today my left breast hurts. It’s a deep pain that is worse when my breast moves or any pressure is applied. I’ve been nauseous for a few days and today throwing up. I’ve never had mastitis and thought it would be strange to have now. Any thoughts?