Welcome to SR! You're in the right place.
If it's any consolation, what you're going through right now is pretty normal. Those first couple of weeks can be tough, both physically and mentally. Some kind of support is really important; SR is a good start and for me it has made a world of difference in my recovery. Can I ask why you're reluctant to try AA? It may not be what you're thinking it is ... the only way to find out is to try one meeting and then see how you feel about it. I'm not saying it's for everyone (it's working for me), but it is worth looking into if it can help you stay sober.
As far as getting through the withdrawals, try to sleep when you can. Get some exercise, even if it's just a couple of walks around the block. Make sure you eat, even if it's something small, and drink lots of fluids (water and Gatorade help a LOT). Keep your head busy with a book or with journaling. Come to SR and hang out for awhile. Just something to distract your mind and body for a little bit at time. And be kind to yourself. You're doing a life-changing thing for yourself and while it takes some time to feel the positive aspects of it, they are well worth the wait.