Welcome to HCM,
You are on birth control pill and you take all pills regularly then it is almost 99% prevents pregnancy
Hence there is very remote chance of pregnancy you should wait for few days and if no period just take a urine pregnancy test to rule out pregnancy other more confirmatory test like Beta HCG
in blood and sonography
may be done with consultation to Gynecologist after few days.
Your sickness may be related to some infection or food poisoning
. If pregnancy is ruled out then Even such acute illness can delay period for few days,other causes are stress, hormonal
You should not worry but take care to avoid any further complications.
Hope this helps
Dr.Akhilesh Dubey M.D.