Down to 15mg of Valium from 30, over 8 months. Quit SSRI because of sexual SFX. Buspar (buspirone) made me very dizzy. Feel very sad and depressed. Any advice?

Many possibilities. Psychotherapy is effective for many anxiety disorders. In addition, sexual dysfunction (SD) with one SSRI/SNRI does not mean that this will happen to all of them, and non-SSRI antidepressants can also be tried. Alternatively, Wellbutrin, even in low doses, may reverse the SSRI-mediated SD. Buspar (buspirone) may have been tried in too high a dose, or escalated too rapidly. Consider second (or third) opinion.