Light cramping and bleeding.. Nervous

I've never had a miscarriage and have two healthy children that are 9&10. I don't remember having any spotting with either of them except for with my daughter at 15 or 16 weeks. So far with this little one I've had very light spotting for a few days and now went to the bathroom and it was brown and red blood and some light dull cramping. We have tried so long to get pregnant and I'm so excited but this spotting keeps making me worried that something is going to happen. I go to the doctor Tuesday 😊