Diary was making me still feel run-down, bloated and gassy so I had to cut it out of my diet until I found a company that has some A2 Beta-casein dairy versus the troublesome A1 that you get at the usual supermarkets. I can now eat dairy again without the yucky symptoms.
Try cutting out the dairy you've been eating for awhile and see if you notice any consistent differences with how you feel.
Its tough to get back into fitness if you haven't done it for awhile and eating better helps to a certain extent but I have found that some days when I workout I feel great and can go hard and then other days I can't do what I just did two days prior. Its a matter of finding the proper balance. When I went back through what I had eaten on both workout days, I found I had more protein before my workout on the day that I did really well.
It is early days still, give it a few weeks of completely clean eating and you will start to feel and see the results. I lose weight quicker when I do ketogenic levels with very low carb, high fats and moderate protein.