*Waves from Iowa* :)
Sounds like a tension thingy to me.
Either top or bobbin might adjust that see if it helps.
Way to check bobbin tension.
Take bobbin case out and leave bobbin in. Grab end of thread and let bobbin and case drop.
Drops fast it's way too loose.
Doesn't drop or drops very very slowly, is prolly lil too tight.
Since you have loops I'd say it's too loose.
To adjust tension turn the lil bitty screw on bobbin case a tad to the right,
just a smidge at a time it doesn't take much to adjust it.
Adjust until you do the above test again til it slowly but steadily drops.