There are varying degrees I think and blocked ducts can def turn into Mastitis. If you have glands working over time to nab any infection that probably isnt helping.
I was told to start feeding from the side that was blocked (so you can be fully emptied) and to massage the lump/s while feeding- it can be sore but it really helps, and lots of water Hope it clears up for you fast. Full on mastitis is fever, shaking, cant think, cant do much at all. its awful.