What Could Cause Sudden Spike In Blood Pressure And Heart Palpitations?

I've always had blood pressure that was 120/80, but last Sunday morning around 1 a.m., I wasn't able to sleep and I got up and my heart felt like it was going to jump out of my chest. I took my bp and it was 184/94. It freaked me out. Since then, I've been taking it and it's been 150/73, 151/86, 137/80, 150/89, etc. and my pulse is high for me: 79 to 84. I just turned 64, and am 5'6", 135 lbs. I work at Curves Fitness for Women, part-time, and my husband and I just came in from a four mile hike/walk. We bike ride, kayak, walk, hike--although, with winter, not as much of that. For years, I've eaten organically and locally grown, mostly. I never eat processed foods. I eat out at a nice restaurant twice a month, maybe. I don't smoke, I drink wine or beer a couple of times a week. Help. What do you think?
Thank you for your reply.
p.s. Organic coffee, 2-3 cups in a.m., but not any since my bp was 184!