ESA + ESA

On 8th November 2018 I received a claim form for ESA. I have had problems with my benefits in the past, so this really stresses me out. (Thanks to your guides I have been successful.). I managed to get it completed & sent back before the due date. However on the due date I received another ESA claim form.! The ESA I get is based on my contributions - this form, ESA3 (IBR) is claiming to be looking at whether I might also be entitled to ESA-income related for the period from 2012 to the present. This came as a surprise to me, and I am not even sure whether I would qualify ! My husband was working full time in 2007. He then worked part-time until February this year. On top of all this I inherited over £30,000 in February this year. I am not sure whether to claim, and if I do there may be a problem with me remembering dates etc. Is there a guide on this extra ESA?