I take Wellbutrin strictly for OCD anxiety. I do not have a history of depression.
I do want to add, though, that Wellbutrin isn't an anxiety med, it's strictly an anti-depressant. If your anxiety is caused by depression, it can work, but it works on depression by being very stimulating. So does Effexor, so that's not a good combo, in my opinion. Wellbutrin is often combined with ssris when they lower sex drive or cause weight gain, but as a secondary med, because of its stimulating properties, but Prozac can be stimulating as well, so if you try that one, you need to see how you do on it first. If anxiety is your main problem, my understanding is that Wellbutrin isn't indicated as a first line remedy.
You may not need anything but the Wellbutrin to be honest with you. I have OCD which leads to anxiety and then to depression. I was on Prozac many years ago and I tried those other drugs over the past year when it reared its ugly head again but I choose Wellbutrin. I was initially on 150 XL like you but I needed a boost when my OCD kicked into overdrive so I went to 300 XL. It did make me more jittery at first but after about 4-6 weeks, it went away and I feel GREAT! I needed a little klonopin during the day in the beginning to combat the jitteryness but once I hit the sweet spot, I was on my way. The reason I stuck with it is because, there is no weight gain or at least I have not gained any. I have not even gained back the 12 I lost during my initial anxiety where I couldn't eat. Also, for me there are absolutely no sexual side affects like with the other drugs and that was an important factor in choosing a medication this go around.
So hang in there and hopefully Wellbutrin will be the only thing you need.