Might be worth calling and asking if you can have an increase. THey may have you do a level but at that low they may not bother. That's the only way they know to increase or not. But if you explain you've been on two weeks and are having issues and would like to know if an increase is possible they'll probably agree. I can't think of anyone I know being close to therapeutic level at 300 and you have to be there (or in a case like mine at a level that works for you safely) before it will help, regardless of mania or hypomania. Generally you need your blood level to be .6-1.1 to be therapeutic. Everyone processes it diferently but it's unlikely that little is giving you much of a level. Even with my body tending to run high on it 450 mg used to get me to only .4 which is what we found is perfect for me. That's unusual though. Generally lithium dose has nothing to do with whether you get full-blown mania or not.

Dose changes can be done every 5 days so you should be able to do one if the dr. would agree.

There's no harm in calling. They are used to it and if you are still having symptoms they are usually glad for you to call rather than risk things worsening.