The widow, and the three days
Two things that a grief course for Muslims cannot leave out.
The Qur'an sets the widow's waiting period at four months and ten days, and a widow is living inside a legal and social state, not only a private sorrow. If that is you, the details of it are a matter for a scholar, and the point here is only that the course knows you are there.
Then the report below, which limits mourning to three days except for a husband. That gets quoted at people badly. It concerns the formal state of mourning and its outward observances, and confirming that framing is a scholar's job rather than ours, but nothing in it puts a clock on sorrow.
And 2:286, that no soul is burdened beyond its capacity. In this topic that verse is genuinely a comfort, and it is worth saying that it is a statement about what you are carrying, not an instruction to cope well with it.
Qur’an and Sunnah
وَٱلَّذِينَ يُتَوَفَّوۡنَ مِنكُمۡ وَيَذَرُونَ أَزۡوَٰجࣰ ا يَتَرَبَّصۡنَ بِأَنفُسِهِنَّ أَرۡبَعَةَ أَشۡهُرࣲ وَعَشۡرࣰ اۖ فَإِذَا بَلَغۡنَ أَجَلَهُنَّ فَلَا جُنَاحَ عَلَيۡكُمۡ فِيمَا فَعَلۡنَ فِيٓ أَنفُسِهِنَّ بِٱلۡمَعۡرُوفِۗ وَٱللَّهُ بِمَا تَعۡمَلُونَ خَبِيرࣱ
If any of you die and leave widows, the widows should wait for four months and ten nights before remarrying. When they have completed this set time, you will not be blamed for anything they may reasonably choose to do with themselves. God is fully aware of what you do
Qur’an 2:234
لَا يُكَلِّفُ ٱللَّهُ نَفۡسًا إِلَّا وُسۡعَهَاۚ لَهَا مَا كَسَبَتۡ وَعَلَيۡهَا مَا ٱكۡتَسَبَتۡۗ رَبَّنَا لَا تُؤَاخِذۡنَآ إِن نَّسِينَآ أَوۡ أَخۡطَأۡنَاۚ رَبَّنَا وَلَا تَحۡمِلۡ عَلَيۡنَآ إِصۡرࣰ ا كَمَا حَمَلۡتَهُۥ عَلَى ٱلَّذِينَ مِن قَبۡلِنَاۚ رَبَّنَا وَلَا تُحَمِّلۡنَا مَا لَا طَاقَةَ لَنَا بِهِۦۖ وَٱعۡفُ عَنَّا وَٱغۡفِرۡ لَنَا وَٱرۡحَمۡنَآۚ أَنتَ مَوۡلَىٰنَا فَٱنصُرۡنَا عَلَى ٱلۡقَوۡمِ ٱلۡكَٰفِرِينَ
God does not burden any soul with more than it can bear: each gains whatever good it has done, and suffers its bad- ‘ Lord, do not take us to task if we forget or make mistakes. Lord, do not burden us as You burdened those before us. Lord, do not burden us with more than we have strength to bear. Pardon us, forgive us, and have mercy on us. You are our Protector, so help us against the disbelievers.’
Qur’an 2:286
Narrated Humaid bin Nafi`:Zainab bint Abu Salama told me these three narrations: Zainab said: I went to Um Habiba, the wife of the Prophet (ﷺ) when her father, Abu- Sufyan bin Herb had died. Um ,Habiba asked for a perfume which contained yellow scent (Khaluq) or some other scent, and she first perfumed one of the girls with it and then rubbed her cheeks with it and said, "By Allah, I am not in need of perfume, but I have heard Allah's Messenger (ﷺ) saying, 'It is not lawful for a lady who believes in Allah and the Last Day to mourn for a dead person for more than three days unless he is her husband for whom she should mourn for four months and ten days
Sahih al-Bukhari 5334graded sound, sahihaynfull report
Translation: M.A.S. Abdel Haleem, The Qur'an, Oxford University Press, 2004.