Losing weight and fast... problem?

[Holysnap]

Hey i'm a 22 yr old college student and i've recently made some big life changes in the past 3 weeks. I've gone cold turkey on the college lifestyle you could say. I've switch from pizza, cheese steaks, fried foods and NO exercise on a daily basis to eating healthy and exercising 5-6 days a week.
I've eliminated all calories from my drink on a daily basis basically drinking only water or some flavored waters when it gets boring.
I've been eating a healthy breakfast which i never used to eat and then lunch, and dinner around 8pm. I never eat anything past 8pm and i've been snacking on fruits and some veg's throughout my day between meals.
I've started a cardio routine on a local bike trail which is about 4 miles long i can't run it all yet but i'm walking less and less everyday. Then at night while i catch up on my Tv shows i peddle on my bike usually doing 6 or 7 miles in 24 miles {which i guess is a moderate pace} roughly 17-18 Mph.
When i started about 3 weeks ago i was about 275lbs and now i'm down to 258 the lowest i've weighed since high school probably =] I'm really excited about this plan but should i be worried about anything? dropping so much so quick?
I'm defiantly not starving myself or depriving myself of nutrition. I eat some fish several servings of fruits and Veg's everyday. The salad i make at school is {spinach broccoli Kidney beans carrot sticks croutons Cheddar cheese <--- not sure if it's low fat and Ham cubes or chicken chunks Pending what i'm feeling. and Ceaser dressing 3-4 tbs.
I'm feeling the best i've ever felt and i'm not sore or tired and the workouts are becoming easier and easier. it barley feels like work anymore=]. Does anyone see any problems with what i'm doing? should i be concerned with anything physically or mentally?

[Caryopteris]

You might enjoy watching the TV show The Biggest Loser.  They are trying to do what you are doing and it might be fun for you to do it along with the contestants.  

It will help you see that the body sometimes hits a plateau, and what the trainers do and say about it.  It will pass and your progress will resume, so you can't let it discourage you.  It sounds like you are doing great.  Before too long you will think of fast food as kind of dirty, believe it or not, and it doesn't even sound good.  

[Barb135]

You're averaging about 5 pounds weight loss/week, which is a bit higher than the recommended 1-2 pounds, but you've made some drastic changes, also.  If you can maintain this as a lifestyle, you will probably be okay, as the weight loss will likely slow down some.

Do make sure you change up your exercise routine periodically, because if you do the same thing every day, your body will become used to it and it will no longer be a challenge for your muscles.  While you shouldn't hurt after exercise, your muscles should be challenged.

[FurballsMom]

If you're able to exercise enough without over exercising and can maintain this as a new lifestyle, and aren't apt to go back to the sedentary lifestyle it seems like what doctors only dream their patients would just do.  If you do have to cut back some, it would only be some.  So, I wouldn't worry too much about it.