during/over/in the past two weeks + the simple past tense

I haven't heard that.

Does it mean it's OK to use the simple past in my own sentence?

We often use the present perfect with time adverbials which refer to the recent past:

just; only just; recently;

Scientists have recently discovered a new breed of monkey.
We have just got back from our holidays.

or adverbials which include the present:

ever (in questions); so far; until now; up to now; yet (in questions and negatives)

Have you ever seen a ghost?
Where have you been up to now?
Have you finished your homework yet?
No, so far I’ve only done my history.

Speakers of American English generally use the present perfect tense (have/has + past participle) far less than speakers of British English. In spoken American English, it is very common to use the simple past tense as an alternative in situations where the present perfect would usually have been used in British English. The two situations where this is especially likely are:

1. In sentences which talk about an action in the past that has an effect in the present:

American English (AmE) / British English (BrE)

Jenny feels ill. She ate too much. (AmE)
Jenny feels ill. She's eaten too much. (BrE)
I can't find my keys. Did you see them anywhere? (AmE)
I can't find my keys. Have you seen them anywhere? (BrE)

2. In sentences which contain the words already, just or yet:

American English / British English

A: Are they going to the show tonight?
B: No. They already saw it. (AmE)
A: Are they going to the show tonight?
B: No. They've already seen it. (BrE)
A: Is Samantha here?
B: No, she just left. (AmE)
A: Is Samantha here?
B: No, she's just left. (BrE)
A: Can I borrow your book?
B: No, I didn't read it yet. (AmE)
A: Can I borrow your book?
B: No, I haven't read it yet. (BrE)