Desperate for input

Ok. Started out my bf and i have regular sex. Im usually on birth control but almost two weeks ago i stopped the pill for five days at the suggestion of my gyno. He always pulls out. A week and a half later, i get strange cervical cramps out of nowhere and start feeling immensely bloated. I freak out of course and get a pregnancy test. Its negative, but the sex was only a littlenover a week ago at the time. I took two more the next day, still negative obviously. Days go on and i feel more symptoms. Huge headaches come on, as well as back aches, nausea, gas, and more cramping. I started my period this morning but it is extremely light. Like 1/8th as light as my normal flow. Ive had negative tests but my nausea is getting worse as is the bloating. What is happening to me i am so lost