Ahead of a first game of the new season against Cardiff on 7th August, the centre-back has admitted he is still reeling from the drop into the Championship.
But Tomkins is eager for the experience to be short-lived and thinks relegation should be used as a motivation for West Ham, who are now managed by Sam Allardyce.
The 22-year-old told London24: "It is still hard to get over it now really.
"Realising that we are in the Championship this year really hurts, it hurts me as much as it hurts anyone else.
"But we are looking to bounce straight back up now and relegation is something in the past."
Tomkins added: "We are under a new manager now and hopefully we can start on a new era and we can go on from here and get straight back up."