Breast lump... Help!

I have been having incredibly sore breasts for the last couple of days and I assumed that it was a mix from the cold, wearing a too big sports bra and my period coming, but two days ago I noticed that it was only my left breast feeling like my nipple had been pierced, it also has created a huge lump right under and around my nipple, it's red extremely hard and it hurts like hell. Last night when I was taking a shower I saw a little dot of white so I pushed a finger into my breast and out poured a heap of brown and white puss like discharge almost. Today there was a slight improvement over the pain by not by much and the swelling has gotten worse. Nothing else has come out of my nipple since last night but I'm wondering if whatever it is will go away on its own or maybe seeing a doctor might be a smart move.

BTW I had a quick check online but all I could find where breast feeding related problems, I'm only 15 and have never had any problems before.

Please help me!!