So I had a misscarriage in January and still felt nauseated still afterward so I went to the dr and…

So I had a misscarriage in January and still felt nauseated still afterward so I went to the dr and they told me I wasn't pregnant. But I haven't received my period yet and I'm having bad back pains and real bad headaches. The dr told me to take sinus medicine to help with it but I'm not sick. What do I need to do??