Sometimes the implantation
bleeding of pregnancy
can be miskaken for periods but they are usually of light duration like spotting and develops a week afer the sexual intercourse.
The home pregnancy test can be false negative in the early cases of pregnancy due to low levels of hcg in urine.
In that case the test should be repeated after a week. You should have the sonography
of the uterus and adnexal tissue done to confirm the pregnancy if your test has come as positive.
The periods are also absent in you so it may also indicate the pregnancy amenorrhea