Feeling weird after I eat?

Hi all! I'm 5 weeks 3 days pregnant today! Up to this point I've not had many symptoms except extreme fatigue, hot flashes, sore boobs, and thirst.

This morning at breakfast I had a big wave of nausea but it lasted maybe 5 seconds. At lunch I felt fine but after lunch I got lightheaded, anxious, and shaky. Almost like a panic attack. Now that it's almost dinner time I'm feeling a little waves of nausea coming on again with hot flashes.

Is the way I felt after lunch normal? Didn't know if it's something I should be concerned about? This is our 2nd pregnancy...first was 6 years ago and ended in miscarriage at 9 weeks so I'm nervous about every little thing. Any insight would be fabulous!