D: I'm sorry to hear that. My first experiences with anal sex were very painful as well. I let someone talk me into it, and they had no idea what they were doing.
But no fear! There are many things out there to help us beginners. ^ - ^
First thing first is lube. Sliquid Sassy is a favourite, and so is the Sliquid Organics Gel.
You can find them here: link
Lubes are important because the anus doesn't produce any natural lubrication. Friction = bad. This should help with the pain and make it easier to slide in toys, fingers, or what-have-you.
Speaking of that, the next thing would be toys. After you feel comfortable with a finger or two (if that thought grosses you out, wear gloves or a condom when you do it), you can move up to toys~
I just got myself the Mood Naughty Plug in small. I haven't tried it yet, but it gets glowing reviews. It comes in two other sizes, and it should be a good way to build yourself up:
You can also try vibrating toys and anal beads. A lot of glass dildos can also be used anally. Obviously use lots of lube, take your time, and relax. Go at your own pace.
Also, unlike your vagina, your anal cavity (once stretched) will not re-tighten, or at least not as much. ^ - ~
Oh, and they make beginner kits too, but most of those are made of nasty jelly material. I would just get the small and medium sized mood naughty plugs, or medium and large.