I donated blood two days ago. Have been doing this for years with no issues. Yesterday, though, I had a headache and just didn't feel great. I then realized I had not upped my fluid intake the night before. I went to bed very early, and I'm fine today. Lesson learnt, though!

As for doing more plasma, I think you should call the centre and get some assurance.I had a similar experience some years ago, with blood spouting everywhere, also on a new blouse, but I was still at the centre and all was well.