HI, I was on cephalexin (for bug bite) 500mg 3 times a day for 10 days.....I done with it 2day ago, but last night suddenly I start having back pain, legs and arms pain, chills, stomach ache, diarrhea, nausea and fever...this morning I feel week, stomach ache and diarrhea, I feel very sick. Do you think could be for the same reason , bug bite?