My (22M) girlfriend (24F) is a flight risk... How do I stop her from running?

\*\*tldr at bottom\*\*<br><br>I'll keep this short. Been together 2 years, but the last 8 months have been rough. She had a miscarriage around that time, which obviously was hard for both of us. Afterwards, our relationship kinda died. She stopped doing things she liked, stopped seeing her friends, and stopped seeing me. She started smoking weed all day, every day, which caused her to lose her job. She was constantly cheerful, but also extremely irritable. The cheerful part was annoying because it didn't seem sincere. She already had issues with anxiety and anger, and the weed seemed to amplify that. <br><br>It has gotten better these last two months. She got a new job, and started seeing her friends again. She cut back on the smoking, and started working out. But now I feel as if she's running from something. Everytime her friends ask her to go out, she goes. She had a gym session everyday this week, and she usually stays there for 2-3 hours. I feel stupid for complaining, but she never had time for me. The other day, we had plans to go to a concert. She had a bad day at work, and cancelled. She then went to her friends house, then the gym, and stayed there for 3 hours. She was busy, but it didn't feel like it. Like she was avoiding something<br><br>She also has this bad habit of saying things like "my life is so boring" and "I need a change of scenery". I live in North America, she's from Europe. She constantly talks about going back home. She already has a trip planned, but has been talking about staying there longer than originally planned. I feel like she's planning on leaving. I've expressed my feelings to her. She reassures me, but doesn't give me any real reasons why I shouldn't be concerned. Basically just telling me "don't worry so much" and "nothing is changing". It feels like she's being dishonest<br><br>I want her to be happy, but I feel like she's doing it at the expense of our relationship. Am I overreacting? Is there something I can do to help her feel better without running away?<br><br>\*\*tldr: I think my girlfriend is planning on leaving because of all the changes in her behavior and because she constantly talks about leaving the country\*\*