PLEASE any input to ease my mind :(

Caitlan

I have taken 5 test and they are all positive but I have been lightly bleeding for 4 days. Today it was dark brown with a long clot in it. I have no cramps of any sort. My boobs are tender and feel more full. I had a full period on August 6 and tested positive on August 17 not expecting for it to be positive. I'm worried sick about the bleeding because I didn't get any of this with my first. I've read possible miscarriage or chemical pregnancy. Has anyone gone threw this situation? Any input would be great so I can relax about it. I do have a doctors appointment Tuesday. Thanks!