I did have the tightness for a while too. I swear I could feel my BM's in my belly closer to the skin. But, it did go away. I think everything was adjusting. I did a lot of belly rubs. It made it feel better, and I used a pillow for a while as a comfort. I did get a posture corrector and started wearing in the morning because I was slouching so much because of the tightness. It did help.
What does your stomach feel like when upset? My go to was Chamomile and peppermint tea.

Small meals are good and always walk after you eat to help with digestion.
Find out what kind of exercises you can do for the tightness. I started with a lot of stretching and swimming aerobics helped so much.
You really do not need to "cook" much. Making sure you get the proper amount of protein, fiber, veggies and fruit.
I feel better when I do.
I like to put fresh spinach in as much as possible. I use a lot of different olive oils for flavor.
Scrambled Eggs are great. You can make a batch and have portions for a couple days.
I like to put all kinds of thing in mine.
Spinach, artichoke hearts, bacon, eggplant (I peel and sauté in olive oil and add breadcrumbs) and of course CHEESE. LOL Sometimes I rotate and make pouched eggs with stone ground bread. I luv pasta but, it is way to filling. Hard to control the portion.
I enjoy eating salads too. Mainly romaine and spinach and you can add your vegies and just about anything else you like. I like to cut up chicken and fry up in olive oils and seasoning and put some in the salad or eat cold.
You need to learn to keep portions small.
Yogurt is a must. It can be a meal too. I add fruit, granola and I consider that a meal.
I choose my biggest meal either breakfast or lunch. I do not like to feel full at night.

I talked to all 3 of my Dr's (primary, GI and Colon) about my anxiety issues. Crazy over a year and I still have them. They all said it was normal and that in my own time I should be better.
Heck, I had so many years of this it is hard to think I am "normal" again.
Funny how we can isolate ourselves.
I have not had another diverticulitis episode. When I go out, I am not constantly looking for bathrooms.
Your BMs should get back to normal soon with you being at 6 mths. It took me 8 mths and you will be surprised and excited.

BUT, you must have proper diet and exercise to help with that. I was so worried I would have to take fiber supplements or laxatives. I have not had to take anything to help with that.