You are – in case you get sick or injured – entitled to sickness benefits – so called sjukpenning. Your employer generally pays the first 14 days of illness.
If you are ill for more than two weeks, you will receive your sickness benefit from the Social Insurance Agency – Försäkringskassan instead.
You need to report your illness to Försäkringskassan, in order to receive your sjukpenning. This is generally done online. Try to do this as soon as possible (after getting sick/injured) and don’t forget to add a medical certificate. You generally receive about 80% of your annual income.
Note, that the sickness benefits – sjukpenning has a time limit. You can only get it for 365 days, during a 15-month period.