Yep, I'm scared too. Oddly, in a way, as mostly managing to be pretty calm about the much much worse odds if my DH's brain thing does turn out to be secondary lymphoma.
As I may have said up-thread, I have something cold/flu-like at the moment so am self-isolating as much as possible within the house. Going round with alcohol wipes constantly, touching things like kettle and taps only with kitchen towel, etc. I have odd sort of scratchy sore throat, occasional bursts of high temperature (only for an hour or so every day), tight chest and breathlessness, and new symptom of fluey aching legs, but the cough I've had for a few weeks is oddly better than it was. No idea if this is covid 19, but only thing to do is act as if it is.
At the moment DH still thinks he's going ahead with the lumbar puncture on Tuesday, unless hospital cancels it. My worst immediate fear is if the results mean he has to have chemo now. But if they did do it I suppose it would be in an isolation ward.
I have become a bit of an arm-chair psychologist about the different sorts of fear coursing around at the moment. I think the on-going fear about DH's brain lesion is horrifying but it has a clear structure - around scans and results - and is sort of measured out for each short period. We try not to think too far ahead until we have clearer information. The scary thing about the corona virus is that no-one knows anything, there is no clear protocol, and even though the risk to each of us individually (even with risk factors) is not enormous (and way way less than the risk my DH is otherwise facing) the likelihood is that we will each know someone who is seriously affected. Of course, we each already all know someone who is closely affected by cancer, or the death of people close to them, but it is the fact of all being together in this state of uncertainty that is unprecedented for most of us.