If you are lasting for 3 to 5 minutes after penetration – before ejaculation – there is little wrong with you. Vast numbers of men ejaculate within one minute of penetration so don’t chastise yourself for lasting longer.
Premature ejaculation is not a disease, it’s a psychological condition.
You can learn to control your ejaculation until you want to release it. Your assumption is quite correct about getting hyper and losing control quickly. It is common in the early, exciting days of a new relationship to ejaculate quickly. Most men will know how that feels. Try to relax more and, with experience, you will certainly control this feeling and delay ejaculation.
There are various stop-start techniques you can learn to recondition yourself to last longer. Perhaps during masturbation, you can learn to recognise various pleasurable feelings and what triggers your change from the plateau stage of excitement, to the inevitability of ejaculation.
One tip, though, before trying to change things … just check with your partner on how s/he feels about this, and whether s/he actually wants you to last longer than you do already. Your lover may not be bothered – particularly if you are great at foreplay – and if the 3 to 5 minutes you last, are superb.
Remember … it’s quality not quantity that counts, just the same as it is with penis size.