There is no such thing as an "ideal body weight". During a person's life, one's body weight will go through changes based on their age, whether or not they are pregnant, how much muscle they have, if they get ill or injured...there are a lot of variables!
Also, I have a hard time believing that you are actually seeing flab where you think you are seeing it. I find it much more likely that you are not seeing your body realistically. The height and weight you describe is very slender, and you must be very strong right now with all the activity you describe. I hope you are eating enough to sustain all that activity!
You are concentrating too much on your imperfections. You admit that you are struggling with "disordered body image". Don't focus so much on your body! Work on that "distorted image". Here is an article that you may find helpful: www.sparkpeople.com/resource/wellness_arti
If this has been an ongoing problem, you might also wish to seek counseling for it. Body image disorders can be dangerous to your mental and physical health, and are not to be taken lightly. Good luck!