Are there any Suttas that explain how to deal with (unexpected) life obstacles? It seems that in this regard Buddhism seems to be a bit passive? I might be wrong.
Please see this answer.
I have tried to explain in that answer, using Dhammapada verses, that Buddhism teaches thinking and acting in wholesome and skillful ways. And this can be applied to facing obstacles and challenges in life, which may come unexpectedly.
The suttas include many teachings for laypeople about most important aspects of life. Try searching here: A Constitution for Living: Buddhist Principles for a Fruitful and Harmonious Life.
You could start with pattidana, that is transfer of merits(method in English). That may start to heal some kamma debt. Also, taking precautions not to put oneself in situations (eating healthy and exercising, walking at night in dangerous areas, associating with immoral people, etc). But, to make forward progress in this long sansaric journey consider what the Buddha said in the “Pubbeva Sambodha Sutta (AN 3.103)” which provides a succinct statement on assāda, ādīnava, and nissarana:
“..ko nu kho loke assādo, ko ādīnavo, kiṃ nissaraṇan’ti? Tassa mayhaṃ, bhikkhave, etadahosi: ‘yaṃ kho lokam paṭicca uppajjati sukhaṃ sōmanassaṃ, ayaṃ loke assādo. Yaṃ loko anicco dukkho vipariṇāmadhammo, ayaṃ loke ādīnavo. Yo loke chandarāgavinayo chandarāgappahānaṃ, idaṃ loke nissaraṇan’ti..”.
Translated: “..What are assāda, ādīnava, and nissarana in this world? If one gets attached (paticca) to sukha (bodily pleasures) and sōmanassa (mind pleasures) that is assāda. That gives rise to dhammā (which are the seeds for future suffering, because these are really “kamma seeds”) with anicca, dukkha, and viparināma (unexpected change) nature, and that is called ādīnava. Arising of such dhammā can be stopped by constraining the tendency to indulge in sense pleasures (chandarāgavinayo), and thus getting rid of craving for sense pleasures (chandarāgappahānaṃ)..”.
I've found a simple little positive method to assist with "constraining the tendency to indulge" using a method to heal chronic pain.
One thing to remember while reading the sutta from Suttacentral.net is that anicca is incorrectly translated. Anicca is a much deeper concept that in a nutshell means "nothing can be maintained to our satisfaction" and much more, not just impermanence.
Some kamma vipaka is so strong that it can't be avoided, but you can minimize the effects with medicines, and other changes made to your gati (characteristics) and asavas (cravings).
With metta, Donna :)