Possible panic attack

While shopping today, about 30 minutes after eating I got really hot and my heart was racing/beating hard. I started to feel lightheaded and like I couldn’t breathe. I had to sit down and decided to check my BP at Publix. It first gave a reading of 124/95. I waited 5 minutes and had a sip of water, it then said 154/72. I was still freaking out at that point and cried in the car because I was scared. I should mention I have panic disorder but thought maybe I was having a heart attack or going into labor. I called L&D and they calmed me down a bit. They Said I was most likely a bit dehydrated and panicked once my heart rate went up which made me even more sick and to not trust the publix machine too much. I drank more water and took a nap. I feel a little better but still feeling the effects of the panic attack. Im 34 weeks and 4 days along. The closer I get to my due date the more anxious I get. I’m just ready for our baby to be here :(