Am I pregnant?

For the past few weeks I have had a few symptoms. First I started feeling lightheaded, it comes and goes. Secondly, I started getting bad lower abdominal cramps similar to when I am on my period, then I started having diarrhea occuring mostly in the morning. I thought I might be pregnant but yesterday I thought I had got my period. Usually my period is very heavy and this time I only see spots off blood and blood when I wipe. This morning I woke up and checked my pad and their was no blood at all which is really abnormal for me. I have done some research and I read that you can spot while you are pregnant from implantation bleeding which means that an egg has attatched to the wall of the uterus. It also said that implantation bleeding is usually really light, like pink or even brown and it can be mistaken for a period. Also that implantation can happen before your expected period and I wasn't expecting mine untill next week. I am giving it time to test for pregnancy since I am not sure if this is my period or not. I have been unable to see a doctor because of lack of insurance. If anyone is going through the same thing or has any idea what this might be please let me know. Any comment is appreciated,