I don't no if I am suffering from anxiety

I'm 25 years old I don't no if I am suffering from anxiety . I worry about my heart a lot because I have had palpitations in the past and now I have wore heart monitors and also got ECG and other tests which all came back perfect but I'm still worried all the time. If I feel a tiny pain in my chest instently I'm thinking I'm getting a heart attack even tho my pain in my chest wouldnt even be bad the more I think about the pain in my chest the worse I think it's getting ... This might sound completely mad but even If I found a lump and where on my body the first thing I think is that I have cancer and I no that I don't have it but I think that I have :( this is starting to ruin my life but I am a shy person in other words I don't like to talk to other people about my problems because I always think they have there own problems to worry about :( .. I would be so great full if anyone would reply back and help or guide me into figuring this out thank you