Lost baby at 20 weeks.

We thought this was going to be our rainbow baby, but we lost our sweet baby at 5 months. I just got back from the doctors office and she said the test results came back normal from the placenta and umbilical cord. So NO answers. But I was half way prepared to hear that. I go back the end of next month to do some blood work. (I have to wait 12 weeks from delivery day so that my body flushes out any pregnancy hormones still left). My doctor is suggesting that I start on folic acid (1 mg) and baby aspirin (81 mg) a day to help my blood flow and prepare for another pregnancy when I'm ready.