High blood pressure and heart rate

I went to ER yesterday and was dc w not findings. I still hv the same symptoms today. The ER called to check on me I told them same as yesterday so she called my pcp which he told me to call my on. The on would probably send u back to ER. I asked pcp what preeclampsia was and he said high bp w swelling   I don't hv any swelling these days but I hv off and on for a few months now. Does anyone know what may be wrong? Has anyone experienced this?  I am 34/3weeks. Can anyone explain preeclampsia any better?