I would say that d. is the closest to what you're trying to say.
Here's what your suggestions mean to me as a speaker of American English:
I have a guilt trip
This is an awkward usage. A guilt trip is something somebody else gives you and not something you 'have'. A person might say, 'Oh it's okay if you don't come over to visit. I'll just stay home alone with nothing to do.' They're trying to make you feel guilty that you're not coming to keep them company. They're giving you a guilt trip. You don't have to accept the guilt, but if you do you'd say, 'I feel guilty about not going to visit.' You wouldn't say that you have a guilt trip.
I'm going through a guilt trip
This might mean that somebody's trying to make you feel guilty and you understand what they're doing. You don't necessarily agree with it but you can't figure out how not to feel guilty either. I don't think this is a very common thing to say.
I have a guilt complex
The word 'complex' in this sentence makes it sound like a clinical condition. A psychologist might diagnose you with a 'guilt complex' if you live with a feeling of general guilt or guilt about something that you can't resolve.
I have a guilty conscience.
In this case you feel guilty without anybody having to tell you that you're guilty. You know you did something wrong and you accept that you have a reason to feel guilty about it.