I'll chime in because I did my first hundred or so dives in a wetsuit in Northern California waters (down to about 46 deg).
A 7mm full suit and a hooded vest worked for a while, I suppose once the newness of everything wore off. After that I realized I was cold, and once I started doing a lot of boat dives, the wetsuit wasn't enough. The ride 10-15 miles at 20+ kts got me chilled before I even got to the dive site, and two dives later, I was downright cold. On the way back in, it was unbearable. I broke down and bought a drysuit and wouldn't go back to wetsuits in any water colder than about 65 degrees.
Your tolerance to cold might be similar to mine. It could be that your wetsuit is wearing out, or it could be that you finally realized that you've been cold all along and now want to do something about it.
A drysuit is a very versatile piece of gear and the good ones last a LONG time and are almost as comfortable as a wetsuit. You can vary the underwear to deal with any water from 28.5 degrees to 70+ degrees. You might want to reconsider going dry.