Nothing to worry about whatsoever (there seems to be some sort of nervousness with SSSS on here, for some reason).
If you are travelling with someone else, give them as much/all of your hand luggage (basically defeating the purpose of this 'security' charade) before the SSSS area and your search will be much quicker. Keep hold of your BP/passport, however.
I would get to the gate about 5mins earlier than normal, no need to be much more early than that. You could flag to gate staff that you are marked SSSS and 'board' you prior to the main rush in order to start with the screening.
Overall, it is a US-mandated security charade that does nothing to improve security, except employing a few additional agents that we all pay for. A waste of time overall.