If by the first day of your last period to calculate, you should be 4 weeks pregnant (only if you are really pregnant). Usually women feel nausea, tender breasts, fatigue, or sudden constipation when they are pregnant but some women don't even feel anything. If you worry about whether you are pregnant or not, you can do a home pregnancy test fo find out. If it turns out negative, you can wait for another few more days. If your period still not start, then do another test again. I have an experience that my period was late for over two weeks. I did two home pregnancy tests and they both turned out to be negative. I also went to see a doctor to reconfirm I was not pregnant. Sometimes stress or changes of your lifestyle or your health condition can easily delay your ovulation which results a delay period. So you could be safe and it is all because your period is delay instead of your are pregnant.
You should take a home pregnancy test for now and if it is negative, wait a bit longer time (at least 3 days) and redo anothet test if your period still not come. If it is still negative, I think it is very likey your period is delay for some reasons instead of you getting pregnant.