Should I take the morning after pill?

[namechangedaily]

The first day of my last period was the 18th Jan. Meaning I should be due on this week. Stupidly had unprotected sex and he pulled out mostly in time but not completely.
Should I get the morning after pill? Or will I likely have already ovulated anyway?

Sounds like its probably too late? You know your own body, noone here can answer that for you for definate.

Withdrawal is not a method of contraception. If you don't want a baby, use contraception.

Too late

Too late as in I will probably have ovulated so chances are low anyway? Or too late in cycle for morning after pill to be effective?

I think the morning after pill is most effective the morning after. Some pills are effective 3-5 days after intercourse but the effectiveness reduces as time from the event progresses.
I hope you find a suitable resolution, maybe see your GP or family planning clinic for advice and options.

When did you have unprotected sex? It's not clear from your post.

You ovulate mostly mid-cycle. It depends when you had sex. The morning after pill is generally effective up to 3 days after unprotected sex. Withdrawal isn’t an effective contraceptive.