Mastitis while pregnant?

So I've felt like complete shit all day and just attributed it to the fact that I'm pregnant and already feeling run down...

After work today I just felt like something wasnt quite normal and have been feeling;

Achy

Nauseous

Crampy and sore

Dull headache

Exhaustion

Dizziness

My left breast has been achy and my nipple has felt tingly on and off

My son is 15 months and we are currently trying to slowly wean since nursing has become painful

Like I said my breast is tender but not super red or swollen