Oh, I'm so sorry to hear that. Not fun at all. I was diagnosed with one in October. It started around five weeks, and I had a long month of bleeding, spotting, cramping, general freaking out. Had a couple of ultrasounds where the baby was growing well, but no change in the SCH, and then after a lot of spotting, I passed what I hoped was the clot. Went for a scan at 10 weeks and it was gone!
From what I've heard/read, it's very common for first trimester
SCHes to resolve by 20 weeks. So you do have good odds, despite all the scary info out there. Hang in there, and feel free to message me if you need any more info.
Edit: I was told the same thing about brown blood being good because it's old stuff coming out. So don't worry if that happens to you.