Miscarriage now chemical preg

I had my first miscarriage on Good Friday in April. Got my first cycle back about 5-6 weeks later. Then, not expecting it, I was 4 days late and got a positive test on Tuesday. Took another Wednesday and Thursday and each one was getting lighter. Yesterday I started bleeding. All night I had mild/moderate cramping and bleeding like a heavy period. Everything points to Chemical pregnancy, so I've read. I don't understand why this is happening again. Has this happened to anyone out there? I feel angry and disappointed in myself.