I couldnt help but quote your post because that's the wisest piece of advice around here.
We should all try and be really careful when it comes to Wazeefahs (I've seen its adverse effect on people and its not pretty). Best (and safest) to stick to the sunnah with regards to dua and prayer. Look at what the Prophet SAW and Sahaba r.a did during times of stress and follow that. There are heaps of Quranic and Masnoon (from ahadith) duas one could use. and the one prayer that the Prophet SAW really encouraged his Sahaba to offer is Salat-ul-haajat (2 nafil followed by haajut ki dua).... if you note the meaning of the dua, it is very much applicable to every stress/ need one could ask for!
Also, invest in some tahajjut prayers. That is one of the most precious times to beg to one's Lord :)