Should I stop worrying about him?

Ever heard of the phrase, "He's just not that into you." If he liked you a lot, he would be making an effort to make time for you. Whether it be texting or ftf. My ex worked 5 jobs and when we were first dating he would come see me on lunch breaks and in between jobs. After a few months, he stopped texting as often and was distant when he was around. Obviously we split, but now we are friends and he said exactly that. Basically lost interest.