How long is homemade strawberry syrup good for?

I made some with berries I picked at a farm last Tuesday. I had a big batch and wanted to split it 3 ways but had nothing to store it in that wasn't plastic (glass decent for giving) I tried to freeze cubes but they are so sugary they are almost pliable and won't pop out of the tray. What to do? Is it bad already 6 days old in fridge in glass dish with locking lid?