Hi Helen
Susan is right, the only way to be sure you really have Diverticular Disease is unfortunately from a colonoscopy or a CT scan, as the symptoms are common to other diseases of the bowel, like IBS, colitis, Crohns.
So did your doctor just pluck Diverticulitis out of the air, give you pills, and send you off with no tests, no information and no follow up (typical for a 10 minute consultation when you have to strip then dress and they have to type up their notes in that time), or was the diagnosis reached in a more scientific way (I have little faith in doctors' general knowledge of this disease as you can tell, and I've had DD for 17 years having previously been told IBS with no testing).
If you had an attack of diverticulitis requiring antibiotics, in addition to the pain you would have had a combination of some of: temperature, fever/chills, swamping cramps, altered bowel movements, tender tummy with hot spots on palpation, back pain, exhaustion, feeling generally unwell. You should have been tested for infection (blood test, wee test). If you have diverticulitis without infection (ie just inflammation) antibiotics are not needed and are usually not given.
All the information in your post here from others is sound. You can expect to feel lousy for a few weeks, particularly as you have been given antibiotics, (the side effects are pretty strong), and have niggling pain and altered bowel movements and frequency for considerably longer. But this disease, which is indeed for life, is manageable with diet and lifestyle changes. I need to avoid gluten and full fat, but I can eat some of the foods others have to avoid.
If you are lucky, and make the changes, you may not get another flare up, or go for years between flares (I had just 3 flares in 14 years, and only then because I got sloppy and ate the wrong things). Many people have multiple diverticula which give them no problems at all - in fact over 50% aged 50+ and 80% aged 80+. This condition is diverticulosis. The blanket term Diverticular Disease covers "itis", "osis", and a general thickening and twisting of the bowel. Not all sufferers have this 3rd symptom, but I do.
Whilst you are on medication it is best to stick to a liquid diet and as you feel better slowly introduce small amounts of low residue food, building up to a healthy diet with soluble fibre. see DiviDiners etc. If you feel twinges and are concerned it is coming back, 48 hours clear liquid diet is advised to give your bowel a rest and allow it to settle down.
Also you should look to taking probiotics to replace the good bacteria in your gut. Pills can't tell the difference between good and bad bacteria so kill the lot off - and that doesn't help you process your food. Lots of advice on here about what's good to take. At the moment I'm trying "live" yogurt. The hardest things are: a) to be patient - it takes time to heal - and there can be good and bad days and b) telling the difference between a healing pain and a recurrence of inflammation or infection. Susan touched on it because it is only human to suspect the more serious.
I wish you well - quickly!