Tension problems (?)

Question

Help! My sewing machine is wacked out! I was trying to sew and the thread kept breaking from the top stich and the bottom stich became loose and tangled in the bobbin area. I would only be able to sew about an inch of fabric before the problem started. The needle would get stuck and not move...and I would literally have to get needle nose pliers out to unsnarl the thread under the needle...what a mess! Not sure if I am explaining this right...I have an older model that has never given me problems...I bought this one in either '94 or '95 and have sewn with it more as a hobby now I am doing a lot of crafting with it. I do occassionally use either rabbit fur or light leather but that has never been an issue until just a few days ago.