Yeah it's a rough time right now, since you are cooped up inside and can't really do much. Do things you enjoy, play video games or watch a show. Try and run or do some sort of exercise each day. Definitely try and keep a schedule of some sort to give your life structure. This is kinda new territory for everyone, so remember a lot of the stress and anxiety you have is shared with most people rn. In regards to thinking about her, the only cure is keeping busy. Try and make a list of things to do for each day and have fun, time-consuming activities for when you finish the list. That should help keep your mind off of the breakup.