Doxycycline Monohydrate and medication

Don't know if it's because of this medication but after taking it twice a day, after only 3 days, I had the most severe headache I have ever had. I couldn't even walk without it hurting. The was followed with me throwing up and this continued right through the evening. When I woke up the next morning the pain was only 25% of what it was the night before and no more vomiting. The next 5 days involved minor headaches that sometimes feel they're on their way to the same severe migraine I first had. Not sure if this is the Doxycycline Mono 50MG but I never had these headaches before and was wondering if anyone can relate to this.

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.