The following are some of the more common symptoms that both psi vamps and sang vamps experience.  This information is from research done on and off of the internet   I would like to point out that alone these don't mean anything and aren't "proof" that you're a vampire of any type.  They are just some commonalties that have been found amongst various vampires.  If you have most of these "symptoms" it doesn't mean that you are a vampire and if you have none of them it doesn't mean that you aren't one either.  As far as I know no actual scientific studies have been completed regarding vampirism.  Therefore the below information should not be taken as a scientific or medical description of vampirism.

Blood hunger:  A symptom most common to a Sanguinarian Vampire.  Similar to an addiction or craving.  This can happen to a psi vampire as well, however, they generally have to be greatly starved for energy.  Psis this will feel a hunger that is more geared towards energy.

Charisma:  Vampires are often reported as being heavily attractive to other people.  They tend to have a slightly higher charisma than most "normal" people.  However, they can also repulse others as well.  Usually this is a trait of a psi vampire due to the fact that when attracted to or repulsed by someone, you are unknowingly giving them energy.  A psi vamp will take this on naturally when they are hungry.  Chemically, the pheromones in their bodies increase causing such an affect.

Digestive trouble:  Many vampires admit to having digestive trouble.  This may be for a variety of reasons but may also be rooted in their constant hunger for energy/blood.  A vampire's body reacts differently to the environment and that includes food.  It is a very rare thing indeed when a vampire has an "iron stomach".

Dual-personality:  Not to be confused with schizophrenia or Disassociative Disorder.  You're still you but you don't act or feel like it.  Generally, this is when one is 'hungry'

Heightened Senses:  Sangs do tend to have this.  Self-explanatory I think.

Medication Sensitivity:  Either a high tolerance for or they affect you differently.  Most vampires cannot take medicine for this reason.  A pill that would make someone slightly sleepy can knock a vampire out for hours!  On the same note, important medicine such as antibiotics may have no affect at all!!

Migraine headaches:  Many vampires report having these.  Also associated with hunger.  Usually psi vampires are the ones who get it the worst.  Their sensitivity to energy makes them susceptible to all sorts of feelings.  When they are hungry, this sensitivity grows to an extreme amount.  Migraines are usually caused from either this sensitivity or the lack of energy itself.  Comparable to a hypo-glycemic.

Night time activities:  Because most vampires are sensitive to sunlight (see below) most of them are more inclined to be active during the night.  Even for those who aren't sensitive to the sun all that much, they tend to be night time people as well.  It is suggested that this has to do with the chemicals in a vampire's body and how they react differently at times.

Psychic Abilities:  Many vampires have psychic abilities.  These include but are not limited to: healing, premonition, energy manipulation, empathy, sensing auras, astral traveling, etc.

Sunlight:  Many vampires feel uncomfortable to some degree in sunlight.  Most have to wear sunglasses because their eyes are so photosensitive to the light.  All too often vampires will wear sunscreen as high as 60SPF or higher.  Some will even wear long sleeves and pants in the hot summer months.  The burns can be anywhere from just a painful red to blisters and sores.  Usually with only being in the sun anywhere from 5 min. to an hour.