What Causes Excruciating Cramps In Lower Abdomen?

Hi, I was bike riding with a friend when he stopped and said he wanted to change bikes. I was fine until I got off, then suddenly I felt dizzy and had trouble keeping my balance. My vision started to swim and everything turned yellow. I tried sitting down for a bit then standing up several times, my friend starting to get concerned once he realized I wasn t over reacting. I suddenly felt the need to go to the bathroom, and sat down once again, I don t remember what happened, but I woke up to my friend slapping me, saying that I had fainted. Someone driving past us called 911, and an ambulance came shortly. However, I insisted I didn t need to go to the hospital seeing that all my vitals were fine, and so they let me out and I felt a lot better. However, the next day we were walking around town when I started feeling what I thought were my period cramps coming on. I asked my friend to wait by the restroom while I went in to put in a tampon. I hadn t made it into the stall when what I can only describe as an excruciating pain shocked my lower abdomen, sending me reeling to the floor of the empty bathroom and the force of hitting the floor causing another ripple of pain. My periods are always fairly mild, and even when the occasional cramp hit, it was not nearly as debilitating as this was. After around 5 minutes of gasping in pain on the bathroom floor i was able to get up alright and hurriedly shoved a wad of toilet paper in between my labia, concerned that I was giving a mini birth to a huge chunk of my uterus. I felt fine until we were in the convenience store searching for pain relievers when I felt the second wave coming. Doubled over the entire way groaning in pain, my friend paid for the medicine and some ginger ale, shoved it in his bag and ran out the door with me in tow. As soon as we sat down on a park bench, I promptly started salivating and vomited for a few mins. Afterwards, I took the medication and tried to poop and felt a big better. I m usually very tolerant to pain, and this whole thing has been very scary. Could it possibly just be my period? I ve never had cramps like those before, and the whole thing with the fainting was just weird.