Hi and welcome!
I'm sorry you needed to find us, though.
Now that you're at the 12 hour mark, it is unlikely you will experience a resurgence of your reaction. Sometimes bi-phasic reactions occur (when a second, often more severe, reaction happens several hours after the first), but they are generally within a few hours. They can
(rarely) occur up to 72 hours later, however, so it's important to remain vigilant after a reaction. Do you have a doctor who could prescribe you an EpiPen to have until your allergist appointment?
It definitely sounds like almond could be the culprit and you've done the right thing by scheduling an appointment for testing. It's important to make sure the doctor who does the testing is a board certified allergist and familiar with treating adults with food allergies, though.
Blood and skin tests are about equal as far as accuracy (around 50% for positive and closer to 90% for negative responses). Some doctors prefer one over the other. Due to the high rate of false positives, it's best not to test more things than are necessary.
Here's a link to a chart you can use to tell how severe your reaction is. Hopefully you won't need it, but it's a good resource until you can see your doctor and get an allergy action plan in place. http://the-clarkes.org/stuff/ana.html