Unexpected dr appointment

I went in today for my 37 week appointment. The dr came in asking about thanksgiving we had a little chuckle and he used the Doppler. All fine and dandy. Then he starts asking me my plans for tomorrow and that I need to call off. Whyyyy???? He said I needed to do a 24 hour urine collection, a non stress test, and some blood work. Wasn't going to explain why...so I asked?! He said my blood pressure was high, there was protein in my urine, I'm very swollen, and I already have low iron which is all concerning this late. I still wasn't really sure what was going on so I asked the nurse and she started talking about preclampsia. So nowwwww I'm freaking out. No work until I see him again next Tuesday. I'm really just trying to think "out loud" but I'm scared that there could be something wrong and a week seems awfully long to go if it is. Or could it be nothing and I'm going to freak out for a week over nothing? Any advice would help?! :/