Looking back at the rest of this thread I really wish I left a more detailed response, especially since I've been through this myself. What I was trying to say is basically a summary of what all the other replies are, that your parents are wishing for too much from you. Hopefully you've made a decision for yourself by now that is healthy for you since today is Tuesday and you have been stressing the importance of tomorrow...

As mentioned, it seems that since you are so close to graduating and that there is a greater chance of you spending even more time away from them than you already have with the research experience they see one of their greatest fears possibly coming true. It doesn't surprise me that you have said they've always been too clingy; parents like that tend to react negatively when faced with the fact that their kids are old enough to be their own person and 'out in the world on their own'...I know mine did. That aside, I really believe that everyone's earlier input is great insight & advice that you can seriously consider.

Well, as others have already mentioned I see two possibilities: either continue being unhappy while they repeatedly violate your boundaries or give them the reminder they need that you are an adult who deserves to be respected for her own needs. You have your own life and they're aware of that, their problem is they fear that they will one day no longer be a part of it so they keep injecting you with guilt to keep you around as much as possible. Knowing college life I believe you're doing an amazing job keeping up with them - you've gone beyond what I've generally seen from people. The problem with that is that by making sure they're getting their wishes met they're not realistically acknowledging yours.

I agree with being truthful about how you feel as suggested; I'll add that since I don't know your familial situation - as in who gets along with who, past instances or anything like that - you can go about that too however you know is best...not that you need me to tell you that I still think it's worth saying though because only you really know what's going on here aside from this.

As easy as it is to focus on the negatives of the situation as we see it, it's obvious that your family is really important to you. When I said do what you want while showing them that your family is still important to you, I meant it is still okay for you to continue to Skype, visit, and fb while you are reminding them of your boundaries. Your actions would show that you have your own life but they're still a priority. This would mean, as already mentioned, doing these things because you want to do them, not because you feel obligated to what they want. And this would also mean visiting them because you want to visit them, not because you feel obligated and most importantly guilty. This last one here leads to resentment and that isn't the best feeling...

Hopefully now you see what I meant in my original response.