The simple answer is: No, because for an important start, worrying is never useful.
But there’s also this: The risk of a clotting complication from the vaccine, if that is a risk at all, seems to be exceedingly small.
On that ever-present other hand, the risk of clotting from COVID-19 is significant.
And then there are all the other risks – and there are many – from a coronavirus infection.
Bottom line: It’s quite unlikely, but not impossible (hence, this will be closely monitored for months), that the AZ vaccine causes clotting abnormalities, but even if there is a small risk, the many benefits of vaccination far outweigh that potential risk.