Need some guidance on wetsuits during the swim

Just completed my second Tri-It Sprint today and am planning on going to a full sprint my next Tri in Sept.  I was able to increase my time by about 34 sec. (1/4 miles swim time 7 min. 55 sec.) and my 100 yd pace from a 1:56 to 1:48.  I worked hard this past month with my swim and it paid off.  I was also first out of the water out of 25 of us.  This is encouraging to me, however, there was a part of the swim (as with my first Tri) that I just felt out of breath and felt like my wet suit was restricting my breathing.  I used a sleeveless this time.  I don't think it was the fit of the wetsuit.  The last bouy to home was actually great and was the best part of my swim.  From bouy 1 - bouy 2 I had to side stroke and once someone caught me I then used his draft to develop my pace again which helped.

I am beginning to wonder about a Full sprint and having to swim a half mile given the struggles I feel I am having with the 1/4 mile.  I don't own a wetsuit so I am renting at this point.  I want to get a perspective and point of view from you experienced Triathletes;  do you think this is a matter of not enough open water swimming in a wetsuit and if I did more open water swimming in a wetsuit I'd be more comfortable in it?  What did others experience at the start? Any feedback and insights would be helpful.

THX