Though I’m probably not the best person to get advice from, here’s what has helped me.
First of all exercise. I’d suggest swimming. I picked up running after several years of not doing it and hurt myself pretty badly since I’m no longer the young person I once was.
The second thing that I am finding helpful is bumble. I’m in no way ready to have a relationship but the lack of confidence I had after losing my life partner was/is so profound. By going to drinks with people I’m able to feel desired again. It feels great to feel wanted again after being dumped by the person who knew me the best. Try to not compare people you see to her, it’s going to be impossible though. Be in the moment as much as possible. Do one date a week. This isn’t about being social or whatever, it’s about prioritizing your mental health. Go on dates with people you’d never consider talking normally (I’m a nerd). For me, seeing finance people, actors, etc in places that I’d never normally go to like a karaoke bar has been the best exercise to forgetting I’ve come up with.
So far that’s it. My goal is to develop as a person, by finding new hobbies and getting passionate about something again. I’m afraid that I will have to wait until after graduation.