I cleaned my machine and now the bottom thread making huge loops and it is jamming up. i have a necchi omega 6015

Have you cleaned under the needle plate
change the needle
make sure the thread has not come off the thread take up lever
some thread & needle don't work togeather--try this
Cut 6-8 inch piece of thread of the spool you are going to use for your project
Take the needle you are going to use for the project
& insert the thread thru the eye of the needle
& lift one end of the thread to a 45 degree angle
& if the needle is the right size for the thread it will slide down the thread
But if the needle hangs on the thread you need one size larger needle for the thread