Hi and welcome to SR. It is a great sign that you took the time to sign up and post before using, it shows you are in the right mindset of wanting to be done with your drug of choice. I hope you can work through this and keep those 17 days going. Some exercise might be a good idea. Or you could treat yourself to a special meal or snack.
I am sorry you are feeling lonely and without friends. Unfortunately in sobriety we often have to stay away from certain people and places. There are a lot of ways to make sober friends though. I know a lot of people who have made amazing friends and connections through AA and NA. What about looking up some meetings if you have never been?