I had sex around the time of ovulation and a week before my period is due I've been feeling dull mild cramps in my lower abdomen. I'm nervous and all the posts I've read up on are saying that it could be implantation. My breasts feel extra whenever I take off my bra and I'm a G cup so I would know what heavier feels like. Please give some advice. According to the calendar my period isn't due until 21st. Sometimes it will be off a day or two and come early or later. I'm nervous to take a test because I feel like it's too early.