bicep injury - strain or tendonitis ?

I am a 20 year old male college student who enjoys lifting hard in the weight room 5 days a week. About 3 weeks ago, I was doing some light weight high rep bicep curls. I immedatly stoped the excersised when i felt a slight pain near the front of the elbow and a stiffness when i contracted my arm in the mid-lower bicep. Well the pain subsited very quickly and in 4 days i was back at it, and really had no problem other than very slight pain in my bicep when i held the weight with my arm extended. well in the last 3-4 days, i have no pain in the bicep, by it has had this feeling of being weak, and feels like jello. I had lifted chest last week, and usually after warming up, my arms and muscles feel tense and taught, but in my right bicep this feeling was replaced with one of being slightly numb and like it was made of jello. none of my lifts went down, but this feeling kinda scares me. what could the possible cause of this be? there is NO brusing or apparent gap in the muscle.