Here's the thing - there's a few ways to answer that and without knowing you well, and knowing your school and life circumstances, it's hard to help, yanno?
But - most (or at least 'many') people find the college load to be exhausting. OMG - a test every other week - how will I survive?! That's normal. And when you stand where you are and compare that load to the much higher workload of professional school, it's normal to ask "how could I possibly do that?" But the thing is, you adapt as you go. You change your study habits, you change your expectations, you get better at learning more efficienty/quickly/retaining, etc. The more you drink from the firehose, the better you get at it. People frequently start vet school, get overwhelmed, and by year 2 or 3 they are on track and managing the load.
So one answer is "don't sweat it - you'll grow to manage it."
But the other answer is - yeah, 2.2 is too low. You need to fix that, and you need to fix it now while you still can. So you have to figure out what's going on and manage the problem. In my experience, the <vast> majority of people who struggle in undergrad aren't putting in the effort they think they are. They aren't studying as much as they should, or their study time is incredibly inefficient (more time talking with friends, texting, facebooking, etc., than actually studying). It's really hard to be objective about evaluating yourself, so ask someone else to do it. Ask someone who is a good studier to study with you and give you feedback. Take advantage of your school's resources, whatever they are, to get you on track. Get on track now, and you still have time to be a great vet school applicant.
The thing NOT to do is to just keep muddling through it using the same study techniques and banging your head on the wall. You need to figure out why you're not doing well and make changes until you're doing better. That can take some pretty hard, honest, critical evaluation of what you're doing.
Don't worry about the summer issue. If you have to take longer to get through undergrad, then do it. It's not a race, although keeping costs down is ideal.
If you want more specific advice, you need to tell us what you're doing to "make it better". What kind of study habits do you have? How much are you studying? How are you studying? What changes have you tried? What school resources do you have available? Have you utilized them fully?
