Hi. My last menstrual period was oct 7 2015. I do have 28 days cycle. My next menstruation was this Nov 4, 2015 but it did not came till now. My last sexual intercourse was oct 23, 2015 we used condom. And now I am 4 days delayed without pregnancy symptoms aside from lower back pain. I also have this yellow discharged and sometimes clear discharged without foul odor. Is it possible that I am pregnant?

You are only 4 days late... far too early to be freaking out about a pregnancy. Every woman will be that late or later without being pregnant before they are 30. And many times more over her life. You should be 14 days late before you take the first pregnancy test if you want maximum reliability with the results. And ONLY take it right after you wake up...the first time you pee that day, or you have to wait until the next day.

Agree 4 days is not really late, had you not had sex, you would just be thinking late cycle. Also the discharges are normally other issues. So as noted, you need to wait till you are at least 10 days, to 14 days late to test

Yes, you could be pregnant, but period could also be off a bit. Give it a bit more time to see if your period shows up. Test, following directions carefully, if still no period.