I remember when I first started shots, I had numerous symptoms and no one seemed to understand. My symptoms were very severe. I have many allergies so I get shots in both arms. Usually one swells more than the other. Sometimes to the size of a softball. Huge. I would be ok during the office wait, but would worsen through the night. Sometimes I'd get very physically ill My throat would get very tight, migraine, rash on scalp, itchy swollen arms, body aches and fatigue. I felt like I had the flu. Often, this would make me feel very imbalanced and make me crave certain nutrients in order to stay clear headed. So I would consume more calories during these periods causing me to gain weight. My doctor often had to reduce the amount of allergen injected because of these symptoms. Of course, this lengthens your immunology period.
Things I noticed helped me each week: Drink A LOT of water the day before and the day of your allergy shots. I notice this is also the biggest preventer of migraines so I now drink 3 - 32 oz glasses every day. Make sure you take your antihistamine the night before your allergy shot. (DO NOT TAKE IT EVERY DAY IF NOT NEEDED. This will dry you out and cause headache, which you might mistakenly believe is caused by allergies). Eat almonds and spinach. These have natural steroids and will reduce inflammation and pain. I know this one sounds obvious but you'd be surprised how much it helps...ice at the injection spot. It decreases swelling and prevents the histamine from spreading throughout your bloodstream, causing a slew of awful feelings. Otherwise, they ARE worth it. I am now testing negative for some allergens. Good luck.