Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 3.5
Situational Awareness; Workload; Distraction; Human-Machine Interface; Confusion
ATC Issue All Types; Conflict NMAC
Flight Crew Requested ATC Assistance / Clarification
Procedure; Staffing; Human Factors
Working satellite and departure combined in the midst of busy season; middle of the day; good VFR weather.  At the time of the event I had 19 airplanes; which is quite busy for this sector and typically would permit a handoff; which I did not have until I asked for one; after it was too late.  Aircraft X departed VNC requesting northbound along the coast.  I assigned AOB 3000 VFR.  Aircraft Y departed SRQ VFR.  I issued climb to 5500; but then amended to 3000 for traffic at 4000 IFR; and additional traffic at 3500 VFR.  I then assigned 3000 to Aircraft X for traffic at 2000 opposite direction.  In the area where the event occurred; there were 5 data blocks overlying each other.  I became distracted with other traffic and missed the CA [Conflict Alert] until after it had happened; at which point Aircraft Y informed me an aircraft just passed by what he assumed to be 500 feet laterally at the same altitude. I don't have a recommendation because during the busy season handoff is often staffed on this sector; but this time the supervisor just didn't realize how busy I'd become.
TPA Controller describes a loss of separation due to data tag overlap and amount of traffic during the session.