What could it be?

Ladies, is it possible to get pregnant right after a miscarriage? I'm asking because I had a chemical pregnancy this month and I seem to be having the same symptoms as before. It could also be that AF wants to pay a visit but I'm not due till the 14th of August. I felt like I also ovulated 2 days ago just by checking my CM and it was clear and sticky. I could be wrong but my body just feels different. I have cramping, sore breast, nausea, etc. I don't understand what is going on with my body. I felt like I had a fever the last 2 days even one of my coworkers said in felt pretty warm. Is this something to worry about or what could it be? Comments and suggestions are appreciated. Thanks ladies!