Any advice please ladys

Amy

I had my period on the 18th and 19th only lasted 2 days and then after I was spotting brown blood on and off for 4 days. On 5th day I had sex with my husband after I was bleeding redish/pinkish blood then stop the next day. I'm still getting achy lower pelvic cramps feeling sick dizzy spells and now and then heartburn. I have taken test and all coming back negative. Does anyone have any ideas why this is happening.