Has anyone had the flu shot yet?

Hi, I have a question. Is anyone familiar with this? I had the contraceptive pill inserted 3 times on Monday. Yesterday, I thought I was pregnant because I had some light bleeding, but it stopped in the evening. Is this the start of something, or could it be something else? I last had the pill inserted in July, and in June I didn't have it anymore because we're trying for a baby. I know it can take up to a year, so I didn't get it inserted again.