I have a lot of heartburn. some weeks i can have none but than others, its constant! acid reflux? gerd? how can i know?

Heartburn: Yes your symptoms suggest you have gerd.You need to avoid very fatty meals, avoid certain foods which make your symptoms worse, like orange juice, pomatoes, mint, alcohol, smokingetc.You can try overthe counter Prilosec or Zantac (ranitidine) for the relief of your symptoms, if there is no relief see you doctor.

Probably: Sounds like gerd which can be intermittent. No one way to make the diagnosis, but if you feel better on a ppi then that usually is enough to make the diagnosis. Diagnosis of gerd can also be made with an endoscopy but not necessary.