generally symptoms don't show until about 4-6 weeks sometimes a test can read negative if you test to soon like a month and under. do keep this in mind, that the common ones are nausea, vomitin,g and feeling swollen abdomen, and not being able to eat because small meals suddenly make you feel full. The best way to figure out is go to your obgyn they can test you there both by blood and urine and discuss the options of your pregnancy if you are. I would do some research because there are clinics that offer free pke apointmenty tests if you make an appointment.
Those don't need to be symptoms of pregnancy, I would say you're just coming down with something - fever and loss of appetite are most signs of being sick than being pregnant.
If your period is late, then taking a pregnancy test with first morning urine will tell you whether you are pregnant or not.