You have given us nothing to go on; what you like, what you choose to eat, what you simply cannot abide, and so on.
I'm not vegetarian, but when I choose to forego meat, I work out in advance whether I want to eat pasta or not; (then the choice is an easy gorgonzola sauce and serve greens on the side; or a tomato sauce, served with onions and garlic, or in autumn, perhaps, with borlotti or cannellini beans; or, if I have lots of time, I'll roast peppers and aubergines [eggplant] and courgettes [zucchini] and add onions and garlic, and make a sauce with that; then again, there is pasta with mushroom sauce - personally, I like to make the sauces myself). Sometimes, I want something hot, so a stir fry with chili, ginger, garlic and various diced vegetables (onions, peppers, garlic, carrot) along with perhaps a dash of soy and oyster sauce might be on the menu....served with either noodles or rice.
Something soothing and easy would be scrambled eggs on toast; or, if you have time try a potato - or root vegetable - gratin and serve that with greens.