20 weeks and moods are horrendous

Is anyone else suffering with really bad moods? I'm 20 weeks today and for the last week my moods have been ridiculous. Crying over the slightest thing to going off on one for no reason whatsoever. I know my partner is suffering because of this. We have our 20 week scan on Tuesday where my student midwife will be there so I don't no wether to speak to her then or ask her to call me on the Wednesday so I can talk to her about this. I'd rather we were in a private room or over the phone to be fair. Is anyone else like this, crying constantly too?! Anything I can do to help prevent this from happening and it pushing my partner away.