Muscle Pain in Both My Calf, Could Not Stand for a Long Time,

I had UTI and my doctor prescribe me the SULFAMETH/TRIMETH
DS 800/160 mg 2 times a day for 10 days. My 1st day I was okay, but on the 3rd and 4th day (I am now on my fifth day) I woke up with a very severe muscle pain in both my calf that I could not stand for a long time. I have persistent headache so I have to take 2 Tylenol every day. My mouth is dry too in the morning. Also, I noticed both my eyes are red that I have to put Visine drops. Is the tablets too strong for me. I am 64 years old but physically fit and only take LISONOPRIL 2.5 mg for maintenance of my blood pressure. Should I continue taking it 2 times a day? Is it okay to take it once a day, but will finished the
20 tablet prescribed? I am 64 years old but physically fit and only take
LISINOPRIL 2.5 MG one table daily for maitainance of my blood pressure. I need an answer ASAP. Thank you