Okay, here's the thing. Too many doctors say "positive ANA" but what matters is the titer. An ANA can go like this:
1:20 - normal
1:40 - still normal
1:80 - borderline positive
1:160 - elevated
1:360 - more elevated
1:720 - highly elevated
It just keeps doubling and the higher it is, the greater the chance of an autoimmune disorder, not necessarily Lupus. Some doctors see the 1:40 or 1:80 and assume Lupus. That couldn't be further from the truth. A slightly elevated ANA can occur with ITP, or can be elevated for no reason at all. The ANA detects inflammation, that's all. A GP once scared my sister like that with an ANA of 1:40. She was referred to a Rheumatologist and she is fine.
You should find out what the titer is. That makes a huge difference. Seeing a Rheumatologist isn't a bad idea since ITP can be a first symptom of Lupus. A basic Lupus screening could be useful at a later time if problems arise. In the meantime, don't worry. This could be nothing. Do you have any other Lupus symptoms such as symmetrical joint pain, fevers, rashes on your face, etc?