I echo what Finn and others wrote. You never wrote here about your having seen a therapist so why not give it a try? If you need a referral, I’m sure you can get one. After all, in searching online, you found this site, right?
Having success in your professional (or personal) is but one step towards feeling fulfilled. Sometimes it takes a lot more. Many of us weren’t brought up in a way that teaches how to easily feel happiness. Some times it is a learned process. However, it is reachable.
You wrote that you have a woman interested in you - in fact, you describe her as your girlfriend. Why would you want victimize her and bring her such sadness? I know a friend who became a victim and that loss of her b/f affects her every day of her life. Depression is curable - even yours. Time heals all wounds.