Miscarriages + d & c

Tuesday exactly 10 weeks I found out my embryo had passed at 7 weeks . I had a d&c done .. Everything was fine .. Not much cramping / barely any bleeding .. More so just spotting  .. Today ( Thursday ) I went back to work & my cramping started to get pretty bad as well as ALOT of bleeding .. Is this normal ? 
How soon after can you try to conceive again ? This is miscarriage number 4 .. My other 3 were very early on so we thought we would be in the clear this time . 
We are devastated .. What kind of tests will have to be done to figure out if there's something wrong ? I have a healthy 5 year old .. It's time for another