help!! out of nowhere I got very severe swelling in my feet and ankles, the night before last. I'd…

help!! out of nowhere I got very severe swelling in my feet and ankles, the night before last. I'd never swelled up or had swelling of any type before then. but now it's so bad that they're extremely puffy and itchy after standing for only 10-15 minutes. when I look closer, there's spots that look like mosquito bites on my toes, ankles, and calves but I haven't spent much time outside lately because of the heat..I'm asked my mom and she looked it up saying it could be cohlestasis....I've also had increased back pain, period like cramps, a bit of watery discharge and baby has been sitting painfully low. do any of you gals know anything about this and should I go in tonight or wait to call my doctor in the morning?? please help, I'm not sure what to do!