Basically, you need to do two things: Rest as much as possible, and try to clear the blockage.
Don't worry about supply for now. There will always be some milk there even if your baby seems more satisfied by something else. It's actually probably more likely that the baby doesn't like the taste, because when you have a blockage the milk in that breast (apparently) goes slightly saltier than usual to encourage them to feed more from that side.
Resting - this is really important to help prevent mastitis. Act as though you are ill - don't try to do anything, lie down as much as you can. If you start to feel flu-like symptoms, then go to your doctor and tell them you have suspected mastitis, they should give you antibiotics to clear it.
Clearing the blockage - expressing with a pump isn't generally a good way as it's almost impossible to put pressure on the blockage area at the same time. You can hand express and massage the lump towards the nipple as well. It doesn't matter if you're only getting dribbles or droplets out, that's fine. You don't need to do it hard enough to hurt, just firmly. Another good way of clearing it is to feed your baby as much as you can on that side, either massaging the lump yourself, or try to get baby in a position where their chin is pointing towards the blockage. Try lying them on their back on a bed and sort of crouch over them(!) Another way is stand in the shower, and "comb" along the boob with a wide-toothed, blunt comb. (Hand expressing in the shower is good too). Heat will help milk release, cold is good at other times just for your comfort.
I don't know what typhus is so I can't advise on that :)