What Are The Side Effects Of Emergency Contraceptive Pills?

i have intercourse with my partner every weekend and we use today viginal contraceptive, and hae missed my periods in oct, then i consultd a gynac he had given me some temporary medicine after having that i got my periods in november but again i missed in december after that again i had dat medicin n got my periods in jan, and got in month of feb, is it sumthing serious m getting worried, will it effect my pregnancy in future