First time with Clomid and Pregnyl

Just a quick intro; my boyfriend and I have been trying to get pregnant for about 2 years now. Even though I ovulate every cycle, my gynecologist prescribed me Clomid and Pregnyl. This is the first month I'm using them. During the ultrasound, I had 2 follicles ready (one on the left and one on the right), so she said there's a chance I could be pregnant with twins.. Well.. That would be quite a coincidence all of a sudden. I'm about 4 days before my expected period, and since this morning I've had a little bit of dark brown bleeding. I've been googling what this could mean, but I find it all very confusing.. It's too late for implantation bleeding, and too early for a period. In the mornings I feel slightly nauseous (the earlier I have to get up, the worse it is), but I think it's all in my head or maybe a side effect of the Clomid/Pregnyl..? Has anyone else experienced this? I sometimes think my period will be so severe that my body can't handle it, and that's why it starts early..
Around ovulation I had severe pain in my ovaries, and now I've been having some odd cramps..
Is anyone in the same situation/ with the same questions or possible answers?