I have bipolar 2 disorder. what's the difference between that and bipolar 1?

Bipolar: Difference is in severity of symptoms. Type 1 is full spectrum of depression and manic episodes. Type 2 is depression with hypomanic episodes.

Hypo mania vs mania: Both usually have depression. Bipolar1 includes mania. Bipolar 2 includes hypo mania. Hypo mania is less severe, but still can have consequences due to impulsivity. Consequences are much more severe with mania. See my other answers for additional details.

Difference: Bipolar I and bipolar II, In the first, manic phases are more severe, and in the second, depressive phases are more severe. There is also cyclothymia which is a low grade version of bipolar disorder in general, where mood swings are not as severe in either direction, manic or depressive.

In short: milder: The short answer is that Bipolar II is milder than Bipolar I but more precisely: While the depressions of Bipolar II may be as severe as those in Bipolar I, the manias of II are not--one experiences not full-blown mania but so called "hypomania"--mild mania. The hallmarks of a bipolar II mania are irritability "hiding" a core of grandiose self-regard. Impulse behavior can be a big part of II as we