I Have Very Bad Cramps In My Loweer Intestines. I'm

I have very bad cramps in my loweer intestines. I'm sure the cause is I have eaten nuts in the last several days. I have mild diarticulous so I know this is bad. I Took one dose of Miralax yesterday morning and one tonight. How much can I take? I do not have the box with details. I've had this years ago and went to the gastrologist. I wass tole to take Miralax every day which I only did for awhile. They told me to eat bland food for now and lots of water. I'm sure I'm npt drinking enoough water.
Please advise. Pains stated higher up moved down low on one side and now across entire lower portion.
I have had several bowel movements today. Not a lot but under normal circumstances probably ok I did not have to strain