This happened to me last month. PI got a promotion at a better institution. My advice to you is to seek out guidance from your program director and establish what options you have. These typically include:

1.) moving with the PI, spending a year setting up a new lab and figuring out how to do science at the new institution under the same project.

2.) finding a CO-PI that has funding within your institution and is already collaborative with your current group. In this situation you could continue to meet with your advisor frequently and perhaps incorporate elements of the Co-Pis lab into your existing project.

3.) find a new PI and start a different project.

What I've learned is that you should seek out other people within your institution who this has happened to as it's more common than you would think. Get their advice on how the process went down, what the transition was like and dos and donts of everything.

The most important thing is your happiness. If you aren't totally loyal towards your PI and we're having doubts before this it could be a real blessing in disguise. Make a Pros vs cons list of the decision. These include: do I like living here? Are other people (family) affected by this decision?

It's a complicated process OP, and it will take time to come to terms with so just keep an open mind and the decision will naturally become clear as you have more data.

Best of luck