Yes you can test yourself for bipolar. There are scales to rate ur symptoms. for example.... Download young mania rating scales and give ur scores for mania Download Beak's Depression inventory do give ur scores.... It's simple, then if u see scores in both scales any point of time in ur life.... It's BIPOLAR.

Consultation with psychiatrist will help. Any psychological disturbances when severe enough to affect your day to day life including your working , social area point towards need for taking specialist help . Rather than labelling yourself , what I feel consultation with psychiatrist is must. The way we don't go for diagnosing physical illnesses on our own. Rather for variation in any of our physical parameters , we approach a physician or a specialist; similarly it is highly recommended to consult a psychiatrist for psychological disturbances.