Hello there,
I can understand your concern. It would have helped to know your age and gender. From what you are describing seems like you have multiple problems.
1) Getting up in the night frequently for toilet: It could mean you have high sugars, or high BP, or if you are a male then some
prostate trouble.
2)Mouth ulcers: Could be
Vitamin B deficiency why you also seem to be anaemic for which you are taking iron tablets.
3) Weakness: Could be high sugars,
vitamin deficiency.
4) Pain in the right side of back: Along with
frequent urination when you have pain in the back it could mean some kidney involvement like infection or stone.
These are my differential diagnosis.
A thorough clinical exam and some blood tests like CBC, Kidney functions, Liver functions,
Thyroid functions, Vit B12 levels, Vit D levels, Fasting and post meal sugars are needed before we can conclude.
Please visit a physician who can guide you based on the reports and exam.
Hope this helps.
Take care.