I am in a situation where I was forced to leave a lab because of lack of funding and the PI leaving. Since, I have taken another lab job, but I am unhappy and frustrated with it. An instructor from my previous lab recently contacted me saying that she has received a large grant and is "reopening" the lab; she asked me if I wanted to come back. I really want to go back, but I am not sure how to approach the situation with my present lab. Any thoughts?