Unusual durations

When I first started experimenting with marijuana ( around 6 years ago ) I would experience intense if not sometimes overly intense highs from very small amounts. No doubt I can easily contribute that to having little to no tolerance or experience with smoking. The strange thing looking back on it though, was how long I would stay high for. Most of the time I would stay equally high without much or any comedown for 6 - 9 hours. For example; If I had a smoke session with my friends at 1 p.m., I would get very very stoned, and stay feeling that way without diminishing until around 8 or 9 p.m. According to graphs and charts I've looked at, the onset, plateau, duration of the high etc usually only has an entire length of around 4 hours. My question is was I hyper- sensitive to pot? Was it simply due to having a low tolerance?