I was diagnosed with pneumonia 5 weeks ago Had 3 lots of Antibiotics it now has nearly cleared but I have a mass on the bottom side of my left lung and have been in chronic pain for 3 days The doctor described Doxycycline as he said its pluresy or he thinks it is. I took first two tablets over an hour ago . Not got sickness but hot tingly feeling in my body. And bit light headed is this normal does anyone know.I also am on lots of tablets for Arthritis . I take omeprazole just need some advice on how to usr these tablets properly.