Pregnancy “flu”??

I am 11dpo trying not to symptom spot nor get my hopes up, but I’ve been experiencing the oddest things. At 7/8 dpo I experienced cramping. Friday and yesterday I have felt so sick. I thought I had the flu. Fatigue and weakness in my entire body, mostly lower back, and a terrible headache. I stayed in bed and slept on/off for two whole days. I’ve been so hungry and emotional as well. Today I feel fine with minimal back pain?? I had a dr appointment Friday and the pregnancy test was negative, but I didn’t get upset because it could be too early. My period is in 5 days and I’m trying to be patient. Sounds familiar to anyone??? I love hearing from others it tends to keep me more calm.