Yo Yo Blood Sugar Readings

I have been sick with a urinary tract infection. I had been running a fever and did not have much of an appetite. Last night when I went to bed at 11:45PM my bs was 196. This is very high for me but since I was sick I ignored it. I was awake at 3:00AM not feeling good and I took my bs and it was 64. I did not fall back to sleep until 4:30AM. I did not wake up until 10:00AM and my bs was 114 which is high for me. What is up with the up and down bs readings since food was NOT an issue? I only ate once today and my bs was normal for me. I am glad that I did not correct my bedtime high last night because my bs took a nose dive between 12AM and 3AM.