33 weeks pregnant with twins?

so im about 33 weeks pregnant with fraternal twin girls and i just feel really weird. I feel completely drained and out of breath just from walking around the house, even when im sitting i find it hard to breathe. I have been having diarrhea yesterday and today, and i feel like there is a lot of pressure in my pelvis area especially when i first wake up. Feels like every time i stand up i have to go to the bathroom, i have a doctors appointment tomorrow but i just want to know if any of you had this before you went into labor. thank you.