Why IS it so HARD?!

In the spirit of a recent post by my friend Jennie, I ask the same question: why is it so hard to lose weight? I have been trying for months now to lose some poundage ever since I moved back home from med school. Once we were settled, and Cory was doing well in school, I figured it was time to take care of myself again. So, I enrolled in boot camp. After two sessions, I was down almost two pant sizes and in the best shape I've been in since having kids.
Well, my knees rebelled on me, and I had a hard time running anymore, and then the holidays came. Bleh. So, my New Year's resolution to get back on track hit, and so did Kevin's terrible twos. No longer wanting to go the child care at the gym, what was I to do? So, on to my parent's rickety old treadmill with a broken console and so loud you can't even hear your iPod through the head phones. Well, I've been doing it. Trying to diet as well, which is really hard living in my mom's house surrounded by all her yummy food. I've lost only 10 pounds since the new year, and that's only if I weigh myself first thing in the morning. Bleh. Three months and 10 pounds?! Not cool. My clothes still fit me which makes me so discouraged. All around me, my friends are shrinking. I have one friend who recently lost 115 pounds! She looks awesome! My sis-in-law just got the best time for a woman in the 5K she ran, and she looks amazing. I have several others who are sharing their weightloss triumphs with me. I'm so jealous. So, what's wrong with me? I'm hungry all the time, running/walking three miles a day and lifting weights killing myself like I did in bootcamp. My mom says that I've grown into my "womanly physic". Whatever. Please tell me I'm not doomed to look like this for the rest of my life?!!