When you jammed the needle did you break it? It sounds like you have a couple of problems going on. Your tension is off and your feed dogs don't sound like they are working properly.
A sign of timing being off is either skipped stitches or the needle not picking up the bobbin thread at all. Your machines symptoms are different. Raggiemom gave excellent advice. Turn the machine off, change bobbin out entirely (just in case you damaged it in some way) and while you are at it, take the hook assembly out and carefully inspect it for damage. Change needle and completely rethread the machine. Also, if you broke the needle you need to go through it very carefully to find the tip of the broken needle. It could be what is messing up your feed dogs.
Unfortunately, if none of these things work you will have to take your machine in for servicing. If you can't afford it then I recommend you start combing your local thrift stores and/or Craigs list for a used sewing machine in working order. Even if it is an old mechanical machine (some are true treasures!). I have seen many posts here where people have picked up sewing machines for as little as $25 and that is much less than a servicing. When you got to check them out, bring thread and fabric to test the machine. Walk away from anything that doesn't work and make a nice stitch.