Doxycycline Monohydrate and stiffness

I've only taken 1 dosage about 5 hours ago for a infected cat bite and I feel soooooooooooooooooo tired. I believe that the tiredness is directly related to the medicine.

I am being treated for lyme disease with 400mgs/day. I take 200mgs in the am and 200mgs in pm. The course of treatment is for 4wks. I am in my 2nd week. I feel just awful. My side effects are nausea, generalized weakness, fatigue, abdominal pain, headaches, joint pain and stiffness. I did not have these symptoms (except joint pain) till I started the meds. I feel worse now than before I started this medication.