I would be grateful for the response and reassing me.

Good morning. My cycles are 30 days old but in March menstruation appeared on the 35th day of the cycle. We already have one child with my husband and we don't want another anymore. I have long been afraid of pregnancy that intercourse from March. I was at bhcg on the last day of March and it came out negative. However, my breasts are swolwn and aching a bit as I touch, and now it has started to slightly ache the lower abdomen/ovaries for menstruation. Yesterday I did a test - pre test and came out negative and after an hour appeared grayish yellow dash.