What Is Causing Skin Rash And Body Ache?

almost two weeks ago, I found a bulls eye ring rash and bite on the back of my right knee. I took a lyme test and it came out negative but the rash has changed (grown in size, sometimes itchy, sometimes not) over the past two weeks. Also, 1 week ago, mid-day I started to feel stuffiness and a headache. I took a long nap and have had a persistent headache ever since. A few days last week it was so bad that I had to wear sunglasses at work. I have pain in the back of my eyes, tenderness on my face and the headache is concentrated around the eyes but also in the back of the head. My neck is also sore and my body/ joints are aching. I have been using a netty pot and hot compresses on my face and eyes thinking that it might be sinusitus. I also have green on my tongue and bad breath. It goes away when I brush teeth but quickly returns with some spots. Also, I'm 29 weeks pregnant. I told my OB about my headaches and she said I can take 2 extra strength tylenol, but it's now been 5 days and I'm taking tylenol often to relieve the pain but no longer helps. Do you think the bite and my headaches and other pains are related? Could this be a problem with my pregnancy?