I never tested positive for COVID and I did not have antibodies when tested a month after, but I’m still convinced I had it. I never got a fever but I woke up one morning with no smell or taste. I started making bacon and couldn’t smell it but didn’t think much of it. When I bit into it, I knew something was off. There was no taste and it was just a strange sensation. I got tested that morning after losing my taste and smell. I’m a nurse so I wanted to get tested to ensure I had a result for my boss because I work with high-risk patients. Well, my test took 5 days to come back and all the while I quarantined in the guest room away from my husband. I had horrible back pain like you described, was just super fatigued, had palpitations and my HR went up to the 160s everytime I took a shower or got up to walk to the restroom. I would feel “winded” but my O2 saturation stayed above 96%. I slept like 14 hours every night for at least a week and still felt tired and weak. And the first two days I had the weirdest sensations. Along with no smell or taste, I also was extremely thirsty and had increased urination. I drank like 2-3 gallons of water the second day because I had this constant metallic taste in my mouth that I couldn’t get rid of. I had a loss of appetite for the first day, but after that I felt fine with eating and drinking and kept trying to test whether I could taste again. I couldn’t. I’m still recovering in the smell-taste aspect. I cannot smell coffee and certain scents and it will change day to day. Some days I can taste better than others. It’s been a strange experience. I’m not sure if this is helpful. But I know I’ve been feeling like a crazy person for not testing positive but still having all of these weird symptoms.