Black outs

by Olivia
(Bridgend )

My white jack Russell has blacked out 3 times in the last week and would like to know if anyone can think of a reason why please? She is 2 years old and has never done it before. She has been very cwtchy the last 2/3 weeks which is strange. She is till her bubbly self but just before it happens she is quiet and won't let anyone near her.

If anyone can suggest what could be wrong I would be very great full

Thanks in advance!