Science

As to why you didn't feel a lot of euphoria, the dose you took was clinical no? When opiates are used clinically doses are typically not aiming to produce euphoria. Many preparations are also slow release.

Euphoria response is highly influences by rate of change of concentration and hence ROI with smoking often being the most (fastest ROI, ~ 5 seconds. Also the most addictive because reenforcement learning is time based) and IV being next. When I was shot up with morphine in hospital as a naive user I burst out laughing as it took effect.

Conversely when I have used opium tea to treat severe nerve pain (I don't advocate this in general) at therapeutic doses and oral ROI I would describe the feeling as powerful analgesia, a strong anxiolytic effect, and a warm feeling of relaxation akin to that after intense exercise (same mechanism) but prolonged.