Regarding period. Only 1 time pls help!

Hlo maine 10 jan ko protected intercourse kiya tha meri last lmp 24 dec ko thi us se pichli 18 nov us se pichli 21 October my period cycle is normally from 28-36 days but in this cycle I didn't get my period my period normally come on that time I am very scared and nervous today is day 45th till now I didn't get my period but I tested blood beta hcg on 21 dec on 23rd dec 26dec 30dec and 5 feb all came negative and with same value of (1.35-1.20) I also tested upt which is negative. From 30 dec to 3rd feb I had taken cirina ncr 15 mg 1 at night but felling cramps in my stomach. Till now no period is I am safe from pregnancy is their any case of delayed ovulation my transvaginal songarphy of 28jan is normal and usg whole abdomen of 9 jan is also normal. I had intercourse only 1 time pls help