Could Back Ache And Dizziness Be Due To Excessive Use Of Antibiotics?

Hello there i m a 64 yr old female having had sigmoid colon removed 10 yrs ago gall bladder 18 months ago and small intestine adhesion removal 9months ago due to sugery i have an on going uti i have had a scan iodine xray and a cystascope and nothing wrong im taking250ml of cefelexin nightly as a maintenance dose and realy for 18 months have taken lots of theses for the infection antibiotics dont agree with me but needs must i keep getting awfull back ache and dizziness also my mood is very low im hoping this is all caused by the tablets thank you . im also having uracyst treat ment to reline my bladder ive had 4 weekly ones and start my monthly ones soon my urine infection had returned agin and im now on nitrofurantion ive been told my kidneys bladder a nd ureatha tube are all ok whats going on thank you