All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
First of all, we congratulate you for what Allaah Almighty blessed you with of following the path of righteousness. What happened to you in those situations should not prevent you from continuing on the path of guidance and obedience. All the children of Aadam (Adam) commit sins, and repenting from sins is required at all times.
Abu Hurayrah narrated that the Prophet said in a hadeeth Qudsi:
"A person committed a sin and then said, 'O my Lord! I have sinned, please forgive me!' and his Lord said, 'My slave knows that he has a Lord Who forgives sins and punishes for it.' Then he remained without committing any sin for a while and then again committed another sin and said, 'O my Lord, I have committed another sin, please forgive me,' and Allaah said, 'My slave knows that he has a Lord Who forgives sins and punishes for it.' Then he remained without committing any other sin for a while and then committed another sin again (for the third time) and said, 'O my Lord, I have committed another sin, please forgive me,' and Allaah said, 'My slave has known that he has a Lord Who forgives sins and punishes for it; I therefore have forgiven My slave (his sin), he can do whatever he likes." [Al-Bukhari and Muslim]
What is meant by the hadeeth is to urge people to repent and not to despair; it is not meant to incite people to sin again and again.
With regard to your promise to your father to study, then scholars held different opinions regarding fulfilling the promise and whether it is an obligation or is only recommended. Most scholars are of the view that it is recommended. Some scholars, however, are of the view that fulfilling the promise is an obligation if it involved any expenses. Please, refer to fatwa 86010. There is no doubt that your father had spent money for your studies, so if you had left your studies without any sound excuse, then you should repent to Allaah and seek the pardon of your father.
Lying is forbidden, and lying is only permitted for a preponderant benefit. Whenever it is possible to use tawriyah (using ambiguous terms to avoid direct lying), then it is more appropriate to do so instead of lying. For more benefit in this regard, please refer to fataawa 84728 and 88412.
Leaving work in places where evil takes place is obligatory as there is a preponderant benefit in doing so. So if the only way to abandon working in such places is to lie, then we hope that you are not sinful for lying. However, the problem is leaving your prayer until its time has passed. This is not permissible except with a legitimate excuse, such as sleeping or forgetting. It is not permissible to delay the prayer for the reason that you mentioned. Hence, you must repent. Please review the conditions of repentance in fatwa 86527.
You should also know that in principle purity is achieved with water, and it is not acceptable to do tayammum (dry ablution) instead of ablution without a sound excuse, such as lack of water or the inability to use water due to an illness and the like, as Allaah says: {And if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women and find no water, then seek clean earth and wipe over your faces and your hands [with it]. Indeed, Allaah is ever Pardoning and Forgiving.} [Quran 4:43]
Finally, we stress what we have said at the beginning, that you should persevere in righteousness and be keen on doing all that which would help you to stay firm on the religion, such as seeking beneficial knowledge, performing righteous deeds, keeping company with pious people, and seeking their consultation regarding the matters that you intend to undertake.
Allaah knows best.