My Boyfriend Had Been Diagnosed With Prostate Cancer And Had

My boyfriend had been diagnosed with Prostate cancer and had his Prostate removed. At the 1st check up Dr. told us that they got it all and looking at the blood test results and the results from biopsy he said that there are no traces of cancer. This was 2 months ago. My boyfriend is now telling me that he does feel like he still has cancer and he is going to die. He says he is just not feeling right. Is there any blood test that could be done to see if there is still cancer in his body so he can stop panicking?