variation in systolic and diastolic measurements?

I have recently received results of a 24 hr blood pressure monitor which resulted in slightly higher systolic results and normal diastolic results.  Doctor has prescribed a mild diuretic - I have a home measurement kit which sometimes shows normal and slighter higher results on the systolic and normal to low on the diastolic (this can at times be as low as 65). Prior to this test I was precribed Fenderil which brought my blood pressure way down to 99/44.   On this basis should I be taking medication- though I have poor kidney function in one kidney all blood tests confirm they are working 100%.