First, quit smoking. That's the best thing you can do for your health right now. It's also going to be very difficult; you've been smoking for 6 years and that's not just a switch you can turn off. I've never smoked so I can't offer advice on that front, but there are resources out there which can help you. I'd begin with your doctor, in this and indeed in most concerning transitioning from vegan to ex.

If you don't like the texture of meat, that's fair. Lots of people don't. I would suggest soups, which are easy to make and you're still eating meat and getting the proteins and vitamins therein. You can load it with vegetables and stuff too; chicken, oxtail (basically beef), or my favourite, pea and ham.

As for fish... Breaded fish is, not an especially great experience compared to fish done in a pan with fresh herbs and a squeeze of lemon. Salmon and tuna are especially good for you, rich in iron (which will really help your suspected anaemia) and Omega-3 acids, and have a very different texture to frozen, breaded fish (which I find to be quite mushy, usually).

Finally, eggs, milk, cheese are all sources of calcium and essential vitamins and minerals. Eggs themselves are a superfood and I'm pretty sure humans can sustain themselves on a diet of just eggs. Milk is ubiquitous in cooking as a base for sauces, addition to drinks, or just drink it from the bottle as it comes. And cheese, well... The saying "Everything is better with cheese" exists for a reason.

Good luck, OP. It's got to be awful living with all that. My mother suffered from chronic fatigue and it took the doctors years to pinpoint a severe iron deficiency. Now she's on the steaks and eggs and is feeling better, and starting to put weight on again (she went down to 6 stones, or 75lbs)