You don’t have to eat meat, but you need to get enough protein, at least .7 g per lb of body weight but preferably around 1g. More than 1.5g is overkill. It helps to divide your protein goals by the number of meals you have and try to hit a per meal goal. There’s no need to count calories or weigh your food or anything if that scares you, but it is good to look at serving sizes and protein content to get a rough idea.
You can try eating more beans and tofu. Bean pasta is a good hack. Seitan is really simple to make, especially if you’ve got a stand mixer and instant pot. You may want to consider getting some protein powder if you’re struggling to get enough through food. You can add avocado and cocoa or nut butter and banana to protein shakes for some extra calories.