We are humans and generally resistant to change. Do you not think that your moods are linked to the frustration of not being able to control a situation? Not being willing or able to change and adapt?
Are you getting enough rest now that you're working a bit more?
Try track your moods daily, and make a note of any external stressors that can be to blame. If you cannot find stressors, highlight this, it could be a sign of BP.
And then make an appointment with your general doctor for him to offer some advice and see how you're doing. He may advise you to see a pdoc for a diagnosis of something