Are you winding adequately? Pulling off the breast and yowling could be wind. After a feed, lift baby to your shoulder so baby's body is quite vertical and rub back for 5 or 10 minutes. There are other winding positions, if you Google. Also look at your feeding position from the point of view of wind - baby's head above the stomach when feeding is good for wind, with a nice straight back and neck.
If not and baby isn't wanting a feed, it'll most likely be sleep that's needed. You often need to work hard for independant sleep (off the breast), so just putting dumny dummy in and hoping baby will go to sleep may not be enough. Two things to try:
Swaddle + Dummy
You don't need anything fancy to swaddle. A flat cot sheet or giant muslin cost a few pounds. The swaddle calm baby down by reducing stimulation and recreating womb conditions.
I'd swaddle, dummy in and some gentle rocking (with dummy in) until asleep. Then put baby down gently, leaving baby with your hand on the chest as put down. Wait for a few moments until deep sleep.
Dummy + Bouncer
Another option is to relentlessly bounce baby in a bouncer (minus the play arch). Position the bouncer on the floor in front of the sofa, dummy in and park yourself on the sofa.
Bounce with your foot with a rhythmic movement. Then be relentless about it. You watch tv, foot bounce non-stop and keep in reinserting dummy as needed.
The dummy and bouncer is my favoured approach.
The doctor diagnosed colic...
Just as a final point, because im not sure if you realise, but this is just the doctor fobbing you off. Colic isn't a medical condition, it just means undiagnosed crying.
The crying itself could be about anything and nothing. It could be baby just being a normal baby. It could be hunger, over tiredness, wanting a cuddle, being too hot, too cold... It could be pain, illness or a medical condition... It could be a million other things. Colic just means crying that you don't know the reason for yet.
RhinoGirl - I'd be happy to help.