You probably feel this way because if you cut junk food out completely and suddenly, your body is shocked by the sudden change. Also, junk food has a lot of sugar, which can make you feel energetic, so when you cut junk food out right away your body isn't used to not getting the sugar you used to consume. My advice is to take baby steps. Cut out candy/ice cream, then chips, then soda. etc. until you are consuming less or none at all.
Ultimately, long-term weight loss requires some short-term behavior change and healthier habit formation. That's why we created our Good Housekeeping Nutritionist Approved Emblem, which exists to help turn smart food choices into healthier eating habits. All GHNA foods and drinks make it easier to find — and eat — good-for-you foods without additional time, effort, and cost. We target the lifestyle-related factors that make healthier eating hard, and find simple but creative solutions that actually work! Look for the emblem on labels wherever you shop for food.