The purpose of the multi at night is very important. It the time that's the longest between doses of alli, and the most likely to ensure that the fat-soluble vitamins (A, D, E and K) are absorbed. Because the capsules block some of the fat in the meal at which they're taken, some of those vitamins that are blocked as well.
I suggest that you keep the vitamin bottle on your nightstand so you remember to take one every night.
If your weight loss has slowed down I recommend that you weigh and measure everything you eat and drink for the next week. Chances are your calories are a bit higher than your realize. It's very easy for that to happen -- and weighing is the only way to know for sure.
Congratulations on working out! That's a great start which is difficult for many people to do in the beginning. If you were doing some of this before you started, then kick it up a notch by working harder - not longer - to burn some extra calories.
I hope this helps. Please let me know if you need anything else.
Pat Baird, MA, RD, registered dietitian