Been a victim of drink spiking?

Immediately tell someone you trust. If you need urgent help, call 999. Be wary of accepting help from a stranger and don't leave with someone you don't know. If you feel unwell, someone you trust should take you to your nearest A&E department. Tell the medical staff that you think your drink's been spiked.

Arrange for a trusted friend or relative to take you home and stay with you until the drugs have fully left your system.

Report it to the police as soon as you can. They may ask you to provide blood and urine samples.

Most drugs leave the body within 72 hours of being taken (the date rape drug GHB leaves the body within 12 hours), so it's important to be tested as soon as possible.

If you're abroad, get help from a travel representative or local medical services, or ask a bar or hotel manager to call local police.
https://www.nhs.uk/live-well/healthy-body/drink-spiking-and-date-rape-drugs/

This is the advice of NHS.UK;

If you have been sexually assaulted, you should get medical attention as soon as possible.

You may need tests to determine whether you have any sexually transmitted infections (STIs), or whether you're pregnant.

You don't have to report an attack to the police immediately if you don't want to.

You can contact any of the following places for advice, treatment or referral to a specialist service (such as a forensic examination):

    a sexual assault referral centre
    a doctor or practice nurse at your GP surgery
    a voluntary organisation, such as Rape Crisis
    the Rape and Sexual Abuse Support Centre national freephone helpline on 0808 802 9999 (12 to 2.30pm and 7 to 9.30pm every day of the year)
    a hospital A&E department
    a sexual health clinic
    a young people's service
    NHS 111

Any forensic evidence that's obtained during tests can be stored while you decide whether to report the attack to the police.

If you are physically assaulted or robbed at all you should report it to the police.

Not at all, often they are used to incapacitate someone who is to be robbed.

Yes, they can be very dangerous when combined with alcohol.

They may come in powder, tablet or liquid form, and don't usually have a noticeable taste or smell.
https://www.nhs.uk/live-well/healthy-body/drink-spiking-and-date-rape-drugs/

Most date rape drugs take effect within 30 minutes, and symptoms usually last for several hours.
But if you pass out, it'll be hard to know the full effect. You may still feel some of the symptoms of a date rape drug after a night's sleep.
Although your symptoms will depend on which substance has been used, they usually include some of the following:

    lowered inhibitions
    difficulty concentrating or speaking
    loss of balance and finding it hard to move
    visual problems, particularly blurred vision
    memory loss (amnesia) or "blackouts"
    feeling confused or disorientated, particularly after waking up (if you have been asleep)
    paranoia (a feeling of fear or distrust of others)
    hallucinations (seeing, hearing or touching things that aren't there) or having an "out of body" experience
    nausea and vomiting
    unconsciousness
https://www.nhs.uk/live-well/healthy-body/drink-spiking-and-date-rape-drugs/