pill causing spots and depression

So I've been on a progestine only pill over the last three months, only this week I've been getting really bad spots, stomach aches and feeling more depressed than normal. I've just got 6 months worth of pills so I don't want to waste them and this weekend I am supposed to be travelling to see my partner so if I quit now I may start bleeding and that could affect sex for us. It might just be my body adjusting but I feel like three months is long enough, and I don't want to jeopardise my skin and mental health if it's a cause of this pill. Opinions?