In the PD screen visit the big blue link at the top that says Beginner FAQ, in there the question is answered how many hits to take for a first time. The answer is not a number, it depends on a few things. If you know now how strong the ones that you have feel you should be able to tell if you want a stronger experience or a weaker one than you had right now.
Feeling like you want it to be over is something I have experienced before when I had not tripped that often yet, and it is really in your own best interest to decide that it is okay to ride it out. The reason is simply that is ISN'T over yet but what you can do about it is let go and relax and turn it back positive again. Even if you wouldn't describe it as a bad part of the trip, still if you feel overwhelmed and basically done then sitting or lying down and letting it wash over you is the best thing to do. Go through it, don't try to go around it because you waste a lot of energy that way.
Doing the DMT and also doing nitrous would be ways to boost the intensity for a new level for a while and it can contribute to feeling like it is too much at some point or you want it to be over with. Nitrous on acid is insane IME, I have the best stories about it but I wouldn't recommend it until you feel more comfortable in a tripping space. Don't combine acid until you don't have to put in much effort to guide yourself through the trip.
At second glance if you had dancing carpets and crazy visions perhaps it wasn't such a weak trip after all, I might have read that wrong. But after all you are the one who can decide these things.
Since your first trip has come to an end and frankly this thread could have been closed much earlier, this is where this ends. You can ask many more questions and discuss it in either the Big & Dandy LSD thread (to be found using the Index) or in a thread especially dedicated to a topic.
Before asking anything please consider if it would be a standard question or not.

Many questions have been asked and answered before.
To conclude: about the euphoria - taking more acid can increase the potential for greater euphoria but also for greater confusion, fear or anxiety. This is dependent on set & setting and the way you are imprinted by them. Make sure you prepare adequately to get a positive outcome.
