You're not likely to get P-tagged (perpetually) unless you end up with a confirmed diagnosis.
One visit to the IMH A&E is probably too brief for them to arrive at any and it is uncommon to finalize your condition there and then unless you already have a significant and relevant history (under a related professional such as a clinical psychologist or a certified counsellor), or were exhibiting abnormal behaviour and got bundled there in a hurry by ambulance, law-enforcement, concerned family, or got a P1 evaluation from the MO (which IIRC he/she is duty bound to get you to IMH immediately), etc.
Even then, not many psychiatrists would be willing to put their stamp on a diagnosis before sufficient observation and follow-up. Many psychiatric disorders do share a number of symptoms and some differ by only one or two.
Your uni placement will not be voided outright just because you went to IMH. However your admission or continued studies can be affected if you are not of mentally stable condition at the time as certified by your psychiatrist (if you were put on follow-up appointments and not discharged, that is). The uni would probably ask for a memo from your shrink for clearance if that happens.
Same goes for your future job but it would also depend on how it can be affected, or affect, your condition (if any is diagnosed). Your doctor's opinion will again play a role in this unless you plan not to disclose your history.
From what you have said it sounds more like a situational stress-related coping reaction and may not necessarily be a psychiatric issue (I can be wrong, your shrink has the final say).
