Also, it may seem more expensive to buy single serve meats, veggies, etc in the store but in the long run for 1 person, its cheaper because you have less food waste.
The freezer is your friend. You buy meat in the same big packs, but then portion it up and freeze it into smaller portions. Same with veggies, cook then freeze. Big pots of things like soups, lasagnes, casseroles etc can be frozen down into individual portions.
Or if you cook a big thing of mince, then you can make a quick chili one night, spaghetti sauce the next, tacos for the next (and I'm usually well bored of beef by then!!!)
Good thing with pasta, rice, potatoes is that you can only cook as much as you need.
And recipies that are designed for 2 are really helpful, enough for 1 meal for supper and leftovers for lunch the next day. Or if its a recipe for 4, I cut it in half.
Eggs- omlettes, scrambled, fried, etc are all really quick and you don't end up making too much.
And well, don't be too hard on yourself if you don't feel like cooking. I often have those moments where cooking for just me seems like way too much work, so a bowl of cereal, some cinnamon toast, a ready meals etc are perfect.