So completely normal to just be unsure and overwhelmed but as everyone has said dr Google is a bad idea. Everyone's diagnosis is different and therefore treatment will be different so general Google advice will set you up to be overwhelmed, freaked out and generally confused because everything won't necessarily relate to your situation even if what you read was about for example er+ cancer.
Diabetes I think all depends on how under control it is but also the treatment plan you have. It may change nothing except monitoring it closer or it could be adjusting treatment to suit your situation too. So I would say don't let it stress you out too much the doctors will know how best to ensure one doesn't effect the other.
Sorry you are in the situation but hopefully talking on this page and asking questions will be helpful to you.