If you do phone up, make sure you have already decided what you want (refund, rebook to a specific date in the future) so that they can deal with it quickly. As you can imagine they are very busy with calls and so you can help by not asking them to talk you through the options.

Not sure what your travel insurance, work, family situation is - May is a long way away and it's possible the flights will be "uncancelled", so if you can put off rescheduling for another month or 6 weeks that might be better than rushing a decision now (despite being more stressful).