Thank you all, very helpful replies.
I'm certain I've been in a calorie deficit for atleast 80 percent of the time, based on the fact I'm not eating much at all and have cut out chocolate and biscuits which were my weak point 
I've been doing intermittent fasting too most days, not eating after 8 or before 11 (sometimes even 12pm - 1pm)
Some days i'd skip breakfast completely then have 4 or 5 Jacobs crackers with a smidgen of bertolli spread, along with a banana or another fruit - that's lunch.
Dinner (tea) has been a mixture of slimming world meals and simply cook recipes, but not massive portions.
I've only had potatoes twice in the last few weeks and even then, not loads of them.
I drink on average 3 cups of tea a day with green milk. I used to have 2 sugars but usually go without now, very occasionally I'll have half a tsp.
Is it the crackers setting me back?
I am so so shit at this nutrient stuff it's quite shameful 
I used MFP last year when I was trying to lose a few lbs before getting pregnant (baby now 3mo) but found the calorie calculations to be way off in my case because I didn't have scales to weigh everything.