Lactose intolerance, weight gain, and the dietary advice I got from the dietist

I figured out I had lactose intolerance. But I wanted to get a doctor confirmation of my suspicions, and also I needed the doctor's opinion because I kept on being sick once in a while without knowing why. I had removed lactose from my diet, I barely ate out, but kept on being sick on a regular basis.
The doctor sent me to a specialist. The specialist sent me to be tested. It was positive. In spite of my insistence that I already was following a lactose-free diet, the specialist sent me to get a dietist advice.
The dietist looked at a food journal I kept for her (all this took forever, I had enough time to record my diet for 2 weeks before visiting the dietist) and literally told me: "I have almost nothing to tell you". According to her I ate a balanced diet. If anything, I ate too little fat (following the usual dietary advice I had become fat-phobic) and too much fiber (?!). I was to cut down the fiber a little, eat more fat, and take a vitamin and mineral supplement. On the fact that I still was getting sick once in a while, and on me being overweight, she told me: "you could be suffering from chronic stress". The solutions: cut down the portions, exercise more. In other words: "you are a glutton and a sloth".
I wasn't very convinced. Cutting down portions meant I was hungry a lot of the time. My portions did not look like a lot to me.
"Exercise more" sounds easier that it is: you need to find the time, the energy to put hours to it. Even "take a walk of 30 minutes every day" is tough. When? At work, when such a thing is frowned upon? After work, when it is dark and cold, and I was hungry? Go to the gym after work, exhausted and hungry after a whole day? Before going to work? The closest gym does not have classes until 10 in the morning, and this means to go to work very late (more frowns). It just didn't work. I tried for a while.
What it did work was  that I was thinking outside the box a little more. It was clear I was headed to desease if I didn't do a lifestyle intervention. Could I have chronic stress? It felt off. I am a nervous person, but also I exteriorise my feelings easily. I don't bottle up. But I didn't write it off as "nonsense". And I was on the hunt for a diet that worked.