No Willpower😞

I’ve been trying to lose weight since March and I haven’t made much progress at all. I’ve been bobbing between 160-155 and I can’t seem to get above or below. At one point, I was at 150, but I somehow gained 5lbs. back within two days. I’m only able to go to the gym twice a week and when I do go, I give it all I’ve got an normally burn around 300/400 calories. My eating is another thing. I can’t seem to stay on board with it. I try to make healthy choices, but I always find some excuse or reason to eat unhealthy foods like “I’ll only have one.” “I haven’t eaten this in a while.” “I’m going to the gym tomorrow and I need something to burn off”. What can I do? I’m tired of being stuck and having no willpower to say “No.”😣