Definitely change your eating habits, 680 calories is an extremely low amount of food. I've had a lot more success not paying too much attention to calories and weights and just relying on what my body tells me and what I know. If I'm hungry I'll eat - starving yourself is not an effective means of weight loss - but I'll eat something healthier than chocolate or something. I've found it really helpful to have easy healthy snacks around, especially grapes or crackers, because I can just munch on them whenever I'm feeling snackish and then my meals end up not being too big
My honest advice would be to stop weighing yourself regularly. Maybe this isn't the best from a physical perspective, but it's helped me mentally a lot. I judge my body on the way I look and feel instead of what the numbers say and it's made me both healthier and happier.
But I really understand how frustrating it is to see what looks to be like negative progress, but believe me, two days is not a significant amount of time in the lifespan of your body. Being healthy takes time, unfortunately, and it's easy to be discouraged when it takes more time than you want. Venting is very much allowed
It's hilarious when people put a pronoun into a sentence in a stupid way. Like 'hi they' instead of 'hi moss'.That shit is so funny to me