Weight loss and weight gain isn't instantaneous. You won't see the results of eating nothing the next day and you won't see the results of a binge the next day.
Also remember that 3500 calories = 1 lb. So if you fluctuate between 1800 and 1400 calories a day (and there's nothing wrong with that - a lot of people calorie cycle as a plan), you have to take into account it's not just that you're eating less, it's HOW MUCH less.
Also if you were sick last night and running a fever, it's possible that you're dehydrated. I always come up many pounds lighter after I've been sick just because my body is screwed up. Weighing while or immediately after being ill is simply a sure way to frustrate yourself, IMO.
Finally, I know 8+ weeks seems like a long time and you're wanting to see consistency, but the truth is that 8 weeks is kinda a blip of time in the overall scheme of healthy eating and losing weight. Giving up on something after 8 weeks is just not giving it enough time.
I would say that you need to really CAREFULLY track your calories for a little bit. Make sure that you really ARE staying between 1400 and 1800. Make sure that you're dead accurate on your portion sizes. Make sure that you're not seeing a loss on the scale and unconsciously rewarding yourself with a little more food the next day (a lot of us do that). Be VERY strict with yourself for a while and see what happens.
And don't give up. This is a process. It takes time and patience.

You will get there .. you've shown you can. You just need to figure out how to handle the ups and downs of it!!
.