My heart rate is beating fast, tightness of chest, and hard to breathe. what do i do? i took diphenhydramine 4 times this week last night was 600mg, night before was 700mg, others were 500.

I : I don't know the cause of your symptoms. It could be a heart attack, an asthma attack, a panic attack etc. With the limited info provided - recommend that you call 911 and request an ambulance. Symptoms of a mycocardial infarction (heart attack) can include: chest pain, tightness, squeezing or fullness. However the pain can also present in the upper back, the upper middle abdomen, jaw, head, teeth or in the arms (left more than right). One could have nausea, vomiting or it could feel like indigestion or heartburn. Feeling short of breath, sweating and just feeling out of sorts can also occur. About a fourth of people have no significant symptoms during a heart attack.