All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
There is no harm for you to work in that store. The fact that some products are made by Jewish companies does not make selling them or purchasing them forbidden, as the Prophet traded with the Jews and exchanged benefits with them and dealt with them.
‘Abdullaah (ibn 'Umar) narrated that the Prophet gave Khaybar to the Jews to harvest it and cultivate it and that they got half of its produce. [Al-Bukhari and Muslim]
Also, ‘Aa’ishah narrated that the Prophet bought some grain from a Jew on credit and gave him his shield as mortgage. [Al-Bukhari and Muslim]
Besides, the Prophet accepted a gift from the Roman Emperor (Heraclius) after the Battle of Tabook and sent him a gift in return, and this goes for other such transactions that do not affect the entity of Islam or harm the Muslims; rather, they benefit from such transactions, and these serve the interests of the Muslims.
In any case, the fact that some lawful products are made by Jewish companies does not make it forbidden to deal with them in principle.
Finally, you should ignore obsessive whisperings and not get carried away with them lest they would spoil your religion and your life.
Allaah knows best.