Welcome, Sheilu! Good to have you here. It sounds like you're in a difficult place, however.

I think your experience as a sub can help you alot as a dom; you know the things that you enjoyed, or fantasized about, or needed to be happy, and you can provide those with a perspective no pure dom could have.

The greater question is whether you can be happy in the role. Is this a type of relationship you want, or are you trying to live vicariously through your sub? If you can't be a dom to dominate, or make them submit as they need to, difficulties will undoubtedly ensue.

Nor should you feel you have to dominate, if you aren't happy with that. Pairs of subs aren't unheard of, and you can still teach your friend as a fellow, rather than a dom. Looking together, you may have better luck finding a good dom.

Hope this helps a little!