Official answer is that the date when the employer-employee relationship ceased deterimines what status you are on. For you, there is some flexiblity. If you did not work for the company for the date 2/15 and after, you are F1, otherwise you are on H1. If you are on H1, you have about two months to do a H-1B transfer safely. If you are on F1, you have same amount of grace time to start a new H-1B from F1. Either way, you need evidence to prove your status. After your F2 is approved, you will have more time to start a new H1-B application.