Weird Discharge

So I’m about 8 weeks pregnant...maybe more I’m not sure but at least 8 weeks. And my discharge has been brown and stringy and gooey. I don’t know why And I’m worried this might be abnormal. I also should state my fiancé cheated on me about 2 weeks ago and then slept with me after sleeping with her, I was unaware he had done it as, ya know why would I think my fiancé would do that? And we didn’t use protection. Is there anyway this could be an STD? I’m really worried. I plan on getting tested Monday.