I have a positive ANA (1:320), joint pain, mouth ulcer, livedo veticularis. I the all other test that doctor ordered are negtive. Do I have lupus?

Possibly. The combination of a positive ANA and livedo reticularis gives me cause for concern. Imo, lupus is a reasonable possibility. The other issue is an antiphospholipid antibody syndrome which can occur secondary to sle. Have you been tested for this? Have you seen a rheumatologist? If not, do both.
Other Possibilities . ANA means you have a high level of anti-nuclear antibody. There are more tests to see if that is homogenous (meaning against one specific component within the nucleus of your cells?) or heterogenous (against many components. The diagnosis will be made on further testing. The heterogenous pattern can be a condition call pmr or poly myalgia rheumatica which is self limiting & rather easily treated.
Need more info. There are defined criteria for the diagnosis of systemic lupus. There is insufficient information in your message to provide an opinion. Please go to this site for info. http://www.lupus.org/webmodules/webarticlesnet/templates/new_aboutfaq.aspx?articleid=380&zoneid=19.