I'm taking symbicort (budesonide and formoterol) for mid asthma, but I'm feeling restless and anxious. Is it normal? It will pass?

Side effect... These are common side effects of beta-agonists, which is one of the meds in your inhaler. You should see your doctor because you may need to adjust the dose, depending on the severity of your symptoms. Do not attempt to adjust the dose on your own because you do not want to risk an asthma exacerbation. These symptoms do tend to decrease over time even at the same dose.
Talk to prescriber! This is likely related to the long-acting bronchodilator (formoterol) contained in symbicort (budesonide and formoterol). Talk to your doctor. You may need high dose inhaled steroids without long acting bronchodilators. Make sure there is no cardiovascular comorbidity. You mention that you are 'mild, ' then why are you on a combination drug? Who has classified your disease - you or your provider, please? (perception issue?).
Use it correctely. Hello make sure that you are using your inhaler correctly you may need to talk to your doctor about prescribing a lower dose of the medication never take more than directed.