Heavy Bleeding 7 Days Before My Scheduled Period

Hi everyone! Can anyone enlighten me?

Me and my husband had intercourse 3 days before my ovulation. In my period calendar chart, it says risk of pregnancy is medium. My monthly cycle is always regular and on time. My period is scheduled to come in June 30 and I started with spots and tiny clots in June 23rd (7 days before my period). Yesterday, June 24 the bleeding was very soft and little (dark red to brownish). This morning it became a bit heavy (red to dark red) plus I am having a light-heavy-light cramping on my lower abdomen (up and down pain but not as painful when I get my regular period cramps)

Can anyone enlighten me if you have experienced a similar issue or condition before? And also what does this mean? Could I be pregnant? Am I having a very early miscarriage? Is this normal? Please help. Thank you