hi there, these home pregnancy
tests are fairly accurate and if it has come negative then most probabely you are not pregnant. It could be a case of mistaken dates and so the result. Do not wait for three months but you can repeat the test after a week again if you do not get your periods. IF you do intend to continue with the pregnancy in case you are pregnant then it is a good idea to consult your gynecologist and get an ultrasound
done to confirm pregnacy and start on prenatal vitamins
. Also if you are of older age then it would be prudent to get the baby's well being checked befor it is too late. Take care.