I have a strange sensation on the tip of my tongue, like i've been eating lemon or lime wine gums, it doesn't go away n make me feel a bit sick!

Vague: Hard to say without a thorough history and exam. Duration, frequency, cause, severity? Could be an inflamed taste bud. I would see a dentist and have it evaluated.

Sensation: Could be from a localized oral problem such as a small cut, a viral lesion, an area of inflammation, etc. Could be from a systemic problem such as diabetes. See your Dentist first. If no oral cause obvious, he/she will refer you on to your physician.