Does it matter WHEN you eat calories

no

meal timing is largely irrelevant.

If you're not losing you don't have a deficit...you are underestimating intake somewhere. Do you use a food scale? Your calorie goal is theoretically a huge deficit from maintenance...even if you go over you're at a deficit provided you are properly recording your intake (which includes precision weights and measures).

As you lose weight you calorie requirements are less...so your deficit shrinks and you lose weight slower and have less margin for error. In the early stages and in particular, when you have a lot to lose...you have a relatively large margin for error so people can get away with eyeballing portions and making a few changes here and there...as you lean out, precision is required.

Meal timing makes no difference for weight loss or metabolism. You really have not given enough information in terms of the weight gain. Three pounds is well within the normal fluctuation of weight day to day and is likely a result of something other than fat gain since the only way to gain that much fat would be to eat 10500 calories over your maintenance calories. Frankly, being concerned that you went 5 calories over makes little sense either as that would have no effect in the big picture, or the small picture for that matter, at all. Realize your calorie goal includes a deficit of likely hundreds of calories, 5 calories would not even substantially effect that deficit and certainly would not remove it.

Oh I should add I eat no more than 860 calories a day because I am never hungry anymore and I'm asleep for the majority of my day. I AM NOT ANOREXIC.... I just don't need the calories

Oh and I drank an ICE 0 calorie drink a couple days ago... Could the fact that it has artificial sweeteners be related to this?

Actually you DO need the calories, nobody can function properly on 870 calories a day and still expect to lose weight consistently. Your body is probably holding onto every calorie it gets because it is getting a bit desperate.

Going 5 calories over isn't going to do a thing. Bear in mind that the calorie amounts written on foods are always an average - they take several 100g portions of mushed up food and analyse it for calories, and the reported amount is the average. If you are using things like 'generic bread roll' to record your calories, even if you are weighing your food the amounts on Myfitnesspal (and anywhere else for that matter) are a rough guideline. If we all eat to our calorie goal around half will be actually eating slightly over the goal and half will be slightly under, yet the majority of people are losing weight. In short, 5 calories is not going to ruin your diet.

I can't work out if you are joking about the ICE drink two days ago or not. You say you aren't anorexic but you do seem terrified about calories and if you want your weight loss to be successful you are going to need to change your mentality from 'desperately trying to lose weight at all costs' to establishing eating and exercise patterns that are sustainable in the long term. An 840 calorie per day restriction does not fit into the latter category.

Timing doesn't matter. It's probably a water weight gain.

Even if you're sleeping a lot, your body still needs calories to support basic functions like digestion, blood circulation, healing, brain function, etc. so you're only fooling yourself if you think you don't really need those calories/nutrients. Research BMR.

155....working out all the time. Could be that you are packing on lean protein and building muscle.

At 860 calories per day, she is definitely not building muscle.

You know your brain runs on glucose, right? Glucose is derived from carbohydrates, which means you have to eat to fuel your brain... Please take care of yourself properly!