what I am ding wrong?????

OK so I have been working out about 5 days a week and a lot of walking on most weekends. I eat any where from 1500 to 1800 a day and burn 500 to 1000 a day depending on what work out I do that day and on some weekend I will burn more then that. My work outs are walking every day for about 1 hour this is a half hour too and from work and on my lunch brake I will jog for about 40 min and then it can be anything from a Jillian Michael to a P90X when I get home depending on how much time I have and how much energy I have. For the most part I eat pretty healthy I think...
Breakfast can be any thing from oatmeal and a banana to a 2 fried eggs with salsa. Lunch I always have something with a salad, like a hard boiled egg, tuna, beans or it could be lots of veggies with rice and beans. Dinners are salad, veggies, My home made or store bought veggie patties. ( I don't eat meat) If you did not see the pattern : ). Also sweet potatoes, sometimes pasta. I do always stay with in my calories and snacks I will have any where for 2 to 3 and it is most of the time a fruit, yogurt with strawberries and or granola. Protein shack with ether peanut butter or fruit. On the week ends I do tend to be a little bit bad. I will eat out and have ice cream and a few drinks but most weekends I still stay with in my calories and I will walk anywhere from 3 to 5 mils on a weekend.
But I have not lost a pound. I have seen some small changes in my body shape but not enough to really make a difference and its been 6 months. So what do I need to do. I have tried eating less for a week and working out more and nothing. I have tried eating more and working out more and nothing. Any suggestions? Need some help.