Help!

1200 calories is the least recommended for a sedentary woman, and that has more to do with making sure you're getting good nutrition. The lower your calories are the harder it tends to be to get in all of your vitamins and minerals.

The lack of weight loss could be a variety of factors, but, especially with a relaxed day every week, it's unlikely to be caused by eating too little. It could be water weight fluctuations (these tend to be drastic when you cut your calories low and then spike them again), TOM, sodium, stress, or you could be eating more than you realize. It's pretty common for us to underestimate how much we're eating, even when we're being very careful to weigh all of our foods and log everything down to the oil in the pan.

If you continue to struggle to get 1000 calories, then calorie dense foods can be helpful. This is a generic list and it's definitely not comprehensive, but anything here can be included in a balanced diet (as long as there are no allergies, medical conditions, obviously):
avocado
cheese
full fat dairy
Greek yogurt
ice cream
peanut butter (or other nut butters)
dark chocolate
less lean cuts of meat (including beef, pork, sausage, etc.)
seeds (chia, flax, sunflower, etc.)
nuts
olive oil
coconut oil
butter
beans and lentils
protein shakes, bars, and smoothies
hummus
beef jerky
cornbread
tuna
full calorie condiments
full calorie sauces & dressings
sour cream
guacamole
whole grain pasta
rice
bacon
whole eggs
quinoa
fruit and fruit juices
pretzels
bananas
scones
muffins (bran, blueberry, banana nut, etc.)
potatoes (sweet, red, gold, purple, white, etc.)
dried fruit (raisins, apricots, plums, dates, etc.)
granola
coconut
salmon
edamame
honey
molasses