Hi, I Am Newly Sexually Active (with Condoms) And Also

Hi, i am newly sexually active (with condoms) and also have recently begun frequent swimming and taking 20,000 IU of Calciferol per day. I have also experienced slight weight gain and bloating for over a month - noticed this BEFORE being sexually active. Now my period is about 3 days late. I am quite sure im not pregnant due to the condoms but because of the late period i am very worried. Could the bloating, new swimming habit or vitamin D supplements have contributed to the late period? Very worried now.