No Tomatoes are not a Citrus.
Citrus Fruits are those that have skin that need to be peeled off before you can eat them and since you can eat the skin of a tomato the tomato is not a Citrus Fruit.
Tomatoes are actually vegetables and not fruits event though they have a lot of tomato juice or water inside of them and they seem like fruits they are actually vegetables.
Tomatoes are actually nightshades and eggplant and potatoes are also included in this group of plants.
Tomatoes are very healthy for you just like other vegetables are.
Tomatoes contain may vitamins and nutrients as well as mineral that you need to keep your immune system healthy and boosted and keep you healthy overall.