i’m always feeling this sense of yearning/ longing for something

Every few weeks/ months, I find myself having this weird feeling where I constantly feel like I’m missing something in my life, but I can’t quite put my hand on what it is. It feels like I’m trapped in my current circumstances and a getaway trip would really help, but I do not have the funds for it. I’m also an international student and my friends at home have not entered college yet, so I can’t really expect them to understand how I feel. I often sit at a place for hours, (e.g at the park or by the lake), wondering about the future and I’m gonna be honest, I’m really scared since I don’t know what the future holds. I don’t know if anyone feels the same way as I do, but I personally have not found anyone my age that I can talk to this about (18M)