You might fell down due to stressful postural hypotension, as you woke up suddenly. Try to keep yourself stress free. More over sudden shocking news leads to mild Angina which is one of the reasons for hypotension. Sometimes you might be sweating at that situation but don't be panic.
Next Steps
Try to keep yourself relaxed first of all.
Health Tips
Try to have a bottle of water which helps to increase pressure and helps you to get normal immediately.