My best friend died and I feel guilty?

[Kate]

She sufferd from heart disease since She was child.But it never looked seriously,She was like a normal teenanger.About 5 months ago,She caught a cold.So She didn't go to school for all this time,but I visited Her regulary and phoned.I thought that everything was ok,cause She looked normal and quite healthly.In January our relationship was in crisis.She didn't want to see me,was angry etc.I suspected that She was afraid of back to school-and it was the reason of Her behaviour.I deciaded to give Her some time and stop to call.But She didn't drop a line.So at begining of Feburary I tried to contact with Her,but I couldn't.I was hurt that She didn't answer.I decided to go to Her house,and know about Her.But I was one day late.Her cousin told me,She had passed away.I couldn't believe in that.I feel guilty-I walked away,I didn't behave like a friend,I realized how wrong I was.I regret not sayin' how She meant for me,not sayin' goodbye.I hope She knew that She always was on my mind...