Hello Good Evening,
As per your description you missed thrice in that cycle, so you little bit more risk to get pregnant. but if you would have not missed then also you could get pregnant because nothing is 100% effective contraceptive
As per now you have probability of either you have delayed periods or got pregnant.
For detection of early pregnancy
there is UPT (Urine Pregnancy Test) kit is available over the counter. You can check your pregnancy by this, around a week or so, overdue your date.