It's normal to have water weight fluctuations throughout a monthly cycle. Feeling sleepy and weak is also normal as you are losing iron; try to eat more red meat, spinach, and beans up to the time your period starts.
Always wear a helmet! I've actually seen "road kill" and it's not a pretty sight, and it's kind of stupid that people would still be alive today had they been wearing a helmet.
Anyway, the kind of bike you get depends on the kind of riding you plan on doing plus the kind of terrain where you...
Are you able to follow recipes? Either get yourself some good cookbooks and/or look around on the net for vegetable recipes that interest you, and go from there.
Yes and no. It's all a matter of calories in-calories out, but...
A lot of otherwise healthy vegetables are goitrogens, meaning they can inhibit thyroid function. This can lead to, among other things, a slowed metabolism.
Too much of anything is really not a good idea.