It's understandable that you would feel low after this break up - especially as you were planning to be married in a few weeks. Yet - you sound like you are aware that you will get back to normal. It takes a bit of time, as you adjust to this change in your life. So - it's opportunity for you to reflect on things, and take your time about the ways that you would like to proceed. Is there any rush about getting involved in another relationship right away? Maybe try not to be so harsh on yourself - for example create some other things to say to yourself (instead of worthless). You are a person who works and you are healthy. There are many areas for a person to get involved, with activities, interests, and other people. Hope you're feeling better soon.