What Causes Nausea,raised Heart Rate And Shortness Of Breath?

I ve been experiencing these symptoms for a few years now. I don t have insurance so I ve never been to a doctor. It occurs almost everyday but some days it doesn t. I have nausea but no vomiting and dry heaving..my heart races so fast sometimes it takes my breath away. It lasts about thirty minutes to an hour sometimes longer. It mostly happens at night but very rare in the daytime. I also get very shaky. I ve even had a few instances where I would just be very shaky. Its always random so I never know when it will happen. Usually a fan on high and cold water will calm it to where its bearable. I just want to know what I can do to feel better.