Trying for a baby

Patient: I am 26 me and my husband are trying for our 3rd baby,we have been trying for 5 months now and ever since trying i have been getting different symptoms but my period always turns up last month it was shorter and so far this month i am 3 days late and am never late i have taken a test this morning and its negative, is it possible to still be pregnant or should i wait a bit longer?