How Can Bloating And Constipation Even After Bowel Irrigation Be Treated?

Question: Hi! ! am a female, XXXXXXX 66 years old, lacto-vegetarian since 1978. No known allergies. Early in october I became constipated and through november struggled to maintain bowel mocvments with the help of mainly lactulose and only very occassional stimulating laxatives when things stopped completely. I normally have one motion per day without any problem, no straining. Last constipated about 10 or more years ago. I had occasional drops of blood due to hemorrhoids (so no faeces test for blood was done) and early december my doctor referred me for a colonoscopy 24th january but everything looked normal. In november I did a 1½L water bowel irrigation to reset my system but was soon constipated again afterwards. No hemorrhoids or drops of blood since Christmas. The stools look very different from usual (small, hard or small diameter / short) even when soft)a nd all this time I was very bloated and even when I had a motion, I only passed a little. After emptying my bowel for the colonoscopi I was again constipated after just a few days. I have until the present day struggled with the help of lactulose with poor results needing frequent assistance of olive oil in apple juice or occassional microlax or 120ml Klyx enema, and am unable to establish normal bowel movements. I now have no spontaneous unassisted bowel movements, though I sometimes have the feeling, but there is only air. I eat a varied diet rich in fruit and vegetables and natural fiber, all the things that promote healthy bowel movement, and drink at least 2L liquid a day. I do execise on a rowing machine, trim-bike and use a hoola-hoop every day and go for walks. I do not smoke, drink alcohol or eat snacks and sweets except for occassional small pieces of chocolate. I take progynova 2mg, calcium 1000mg and Levaxin 75 microgram daily. (These I have taken for years without side effects). I now only manage bowel movements with the help of salt water / lemon flushes 2-3 times a week in the morning. I have no abdominal pain or discomfort other than permanently bloated abdomen and feel fine otherwise, though very tired, and sleep well.
I feel I have come to the end of the road for what I can do to reestablish my bowel movements myself, and before seeing my doctor again with a view to examiations to find out what is wrong, I would really appreciate the advice of a specialist in this field.
Thank you very much!