Increased Heartbeat, Cold Sweat, Dizziness, Tiredness. Is It Anxiety Or Caffeine?

For breakfast I ate some eggs and toast but not much because my kids kept asking for bites. This was at 10am. I was unable to eat very much lunch because I was so hungry by the time I sat down at 1:30pm to eat I ate too fast. I did drink dr pepper steady all day. At about 6pm after I took the kids to the dentist and went grocery shopping I was bringing the groceries inside and it was about 93 degrees outside. My heart started pumping very hard and fast. I broke into a cold sweat and started feeling dizzy. I hurried inside and shoved three cookies in my mouth then ate a peanut butter sandwich some cheese a yogurt and drank some water. I am feeling ok now just tired and my heart keeps having one big bump every so often. I have had issues with panic attacks in the past but it was hard to tell whether they were from a disorder or from caffeine overdose as I used to drink a bunch of coffee and would have panic attacks. They stopped when the coffee drinking stopped. anyway I am trying to figure out if I need to see a doctor for this. right now or soon. I'm just really tired now after this happening. I don't know if it's anxiety. caffeine. or low blood sugar. or something else entirely.