These symptoms are markers of Anxiety disorder and in your case you feel apprehensive with butterflies in your stomach and raised heart rate.
These are aggravated in cases of sudden stress that causes feeling of panicky ( feeling of impending Doom) , tremors and sleep disturbances.
Next Steps
Consult Psychiatrist to start with psychopharmacological intervention and counselling.
Health Tips
ventilating your pent up anxiety would help a lot including Psycho-education about Relaxation techniques.