Scale help/how to eat enough healthily

Hello!

Over the past three weeks, I've been doing a strenuous 6-mile hike up a local mountain three times a week. I've noticed that I've slimmed down significantly... However, I've also noticed that I get very tired during the week. I need a lot more sleep than usual and I still feel ridiculously hungry after eating.

I've done a little bit of research and came to the conclusion that I may not be eating enough and I may be exercising too much. I was hiking 6 miles three times a week and two miles on every day that I wasn't hiking. I've already given myself more rest days and that seems to be helping a lot. My mom is doing the same exercises that I am, but when she uses MFP, she tends to get a but obsessed by the numbers. She's under the impression that the lower you can get below your daily/weekly calorie intake, the better. As a result, she limits the amount of meat that she and I both eat and buys a lot of soy products because she's under the impression that it's healthier than actual meat. I can't really feel too good about eating that much soy products since I know that it's heavily processed. I also know that I'm probably not eating enough, but I'm never given enough for any meal and I'm also really unsure about how to eat those extra calories in a healthy way. I know that I could probably eat an extra 1,000 calories in fast food or whatever, but that seems very counter-inuitive. At the end of the day, I'm still usually at a deficit with my calories and I'm not entirely sure how to make sure that I'm getting the amount that I need on my hike days.

Also, I was weighed yesterday for the first time in a couple weeks. I started out at 149 pounds. Then when I was weighed, I was almost 155! Will my weight continue to jump like that even though I'm losing inches?