Why eating ENOUGH is important

I am really enjoying this new venture with my coworkers in charting a better and more healthy way to live and eat. Eating for me has always been a chore because it seemed my body rarely digested things well. I have a sensativity to dairy and raw veggies, and pork and beef products are not too kind to me either. I could go on and on about the ills and woes, but...nahhhhh. I am doing and feeling much better since I have started this process through fitness pal and I am encouraged to stick with it. I am, however, having a hard time eating all of my calories and today I kinda got the warning message about not eating enough calories. According to what was shared, this could send my body into starvation mode causing my metabolism to slow, and I don't want that. The problem is that I am not hungry here lately and I am wondering if the additional protein is the cause? If any of you are experiencing the same, help me out if you have valuable information. I want to lose weight, but i want to make sure I take the right approach. Blessings.