Weight fluctuates daily and is a very poor short term measure of fat loss - water retention, food volume and yes, poo can all contribute, women's weight additionally fluctuates due to the menstrual cycle - I am always a few pounds heavier around my period and it's gone again the week after.
If you weigh daily just note it down and take the lowest reading of the week as your progress marker. If your behaviour is negatively affected by the number on the scale each morning (I've lost a pound so can have some chocolate, or, I've put on a pound so may as well just eat what I want and start again tomorrow) then STOP weighing for 30 days, get your head down and stick to your cals then weigh at the end of the 30 days, if you are consistent you WILL see results.
Tape measurements of various areas - waist / arms / thighs / hips are a better indicator of progress over time.
1200-1400 calories is fairly low but you are quite short - don't go lower it will be unsustainable and lead to yo-yoing - but do make sure you are tracking properly including cooking oil, milk in teas, nibbles of cheese from the fridge (who me?) Etc. it's very easy to add an extra 200 cals a day by inaccurate tracking which will slow your weight loss.
Ignore exercise for weight loss - think of it for health and body composition only (don't 'eat back' the calories most exercise trackers vastly overestimate energy burnt) trying to increase your daily movement such as steps, walking, general busyness is much more effective at burning calories than 3 x short bursts of exercise followed by being mainly sedentary for the rest of the week
be patient - at your height and with not a huge amount of weight to lose, 0.5 to 1lb a week would be excellent progress and thus easily masked by the natural fluctuations of your body
Consistency is key, if you stick to 1200-1400 calories a day for 30 days at least 80% of the Time then you will definitely see results. Then keep going!
To recap on my essay:
1200-1400 cals a day (average over the week so can 'bank' some for a more fun weekend)
8000-10000 steps a day (on average over the week)
80-100g of protein a day - will preserve muscle mass and keep you full longer
3 X workouts - weight training preferable to cardio
Do the above for 30 days - you will see great results - good luck